(Mark One)

þ		ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 [NO FEE REQUIRED]

o		TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 [NO FEE REQUIRED]

A.

Full title of the plan and address of the plan, if different from that of the issuer named below:

B.

Name of issuer of the securities held pursuant to the plan and the address of its principal executive offices:

225 West Station Square Drive

Suite 700

Pittsburgh, Pennsylvania 15219-1122

 

 

WESCO Distribution, Inc.
Retirement Savings Plan
Index

		Page(s)
Report of Independent Registered Public Accounting Firm			1
Financial Statements
Statements of Net Assets Available for Benefits as of December 29, 2009 and 2008			2
Statements of Changes in Net Assets Available for Benefits for the fiscal years ended December 29, 2009 and 2008			3
Notes to Financial Statements			4-12
Supplemental Schedule
Schedule H, line 4(i) — Schedule of Assets (Held at End of Year) as of December 29, 2009			13-42
EXHIBITS and SIGNATURE			43
EX-23.1

Report of Independent Registered Public Accounting Firm

To the Participants and Administrator of the
WESCO Distribution, Inc. Retirement Savings Plan
Pittsburgh, Pennsylvania

     We have audited the accompanying statements of net assets available for benefits of the WESCO Distribution, Inc. Retirement Savings Plan (the Plan) as of December 29, 2009 and 2008, and the related statements of changes in net assets available for benefits for the years then ended. These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion on these financial statements based on our audits.

     We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States of America). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements. An audit also includes assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. We believe that our audits provide a reasonable basis for our opinion.

     In our opinion, the financial statements referred to above present fairly, in all material respects, the net assets available for benefits of the WESCO Distribution, Inc. Retirement Savings Plan as of December 29, 2009 and 2008, and the changes in net assets available for benefits for the years then ended, in conformity with accounting principles generally accepted in the United States of America.

     Our audits were performed for the purpose of forming an opinion on the basic financial statements taken as a whole. The supplemental schedule of assets (held at end of year) is presented for the purpose of additional analysis and is not a required part of the basic financial statements but is supplementary information required by the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. This supplemental schedule is the responsibility of the Plan’s management. The supplemental schedule has been subjected to the auditing procedures applied in the audit of the basic financial statements and, in our opinion, is fairly stated in all material respects in relation to the basic financial statements taken as a whole.

/s/ Alpern Rosenthal
Pittsburgh, Pennsylvania
June 28, 2010

WESCO Distribution, Inc.
Retirement Savings Plan

Statements of Net Assets Available for Benefits
December 29, 2009 and 2008

		2009				2008
Investments at fair value (Notes 2, 4, 5, and 7)
Shares of registered investment companies		$	177,568,193			$	124,263,627
Common collective trusts			20,074,381				14,054,450
Stock funds and self-directed accounts			15,724,184				11,463,975
Stable Value Fund			109,219,294				105,930,357
RAFI Enhanced Large Company Fund			20,946,580				17,744,056
Participant loans			9,154,053				7,280,126
			352,686,685				280,736,591
Receivables
Employee contributions			746,094				876,896
Employer matching contributions			—				347,561
Employer discretionary contribution			—				8,803,031
Accrued interest			20,496				21,807
Net assets available for benefits at fair value			353,453,275				290,785,886
Adjustment from fair value to contract value for interest in the Stable Value Fund relating to fully benefit-responsive contracts (Note 7)			(4,410,440	)			(2,617,033	)
Net assets available for benefits		$	349,042,835			$	288,168,853

The accompanying notes are an integral part of these financial statements.

WESCO Distribution, Inc.
Retirement Savings Plan

Statements of Changes in Net Assets Available for Benefits
Fiscal Years Ended December 29, 2009 and 2008

		2009				2008
Additions
Employee contributions		$	20,913,407			$	24,682,279
Employee rollovers			1,169,935				1,026,878
Employer contributions (including discretionary contributions)			4,022,410				16,821,370
Net appreciation from shares of registered investment companies			45,493,206				—
Net appreciation from common collective trusts			4,284,853				—
Net appreciation from stock funds and self-directed accounts			4,899,661				—
Net appreciation from the Stable Value Fund			5,105,486				4,872,830
Net appreciation from the RAFI Enhanced Large Company Fund			5,372,105				—
Interest and dividend income			4,237,192				7,904,455
Total additions			95,498,255				55,307,812
Deductions
Net depreciation from shares of registered investment companies			—				88,135,613
Net depreciation from common collective trusts			—				5,559,051
Net depreciation from stock funds and self-directed accounts			—				8,420,085
Net depreciation from the RAFI Enhanced Large Company Fund			—				12,558,099
Distributions to withdrawing participants			33,903,237				34,229,706
Administrative expenses			721,036				983,036
Total deductions			34,624,273				149,885,590
Net increase (decrease)			60,873,982				(94,577,778	)
Net assets available for benefits
Beginning of year			288,168,853				382,746,631
End of year		$	349,042,835			$	288,168,853

The accompanying notes are an integral part of these financial statements.

WESCO Distribution, Inc.
Retirement Savings Plan

Notes to Financial Statements
December 29, 2009 and 2008

1.		Major Features of the Plan
		Background
		WESCO Distribution, Inc. Retirement Savings Plan (the “Plan”) was established as of February 28, 1994 (date of inception). At the date of inception, certain employees of the predecessor company became employees of WESCO Distribution, Inc. (the “Company”) and participants in the Plan. At the date of inception, all funds held by the prior plans of the predecessor company related to the employees of the Company were transferred to the Plan.
		The Plan is a participant-directed defined contribution plan covering certain employees of the Company and former employees with a fund balance of at least $5,000 who elected to maintain their funds in the Plan. Former employees cannot make contributions to the Plan.
		Participation for eligible employees requires an employee to be scheduled to work at least 1,000 hours per year and requires an employee to be paid through the Plan sponsor’s payroll system.
		Contributions
		The Plan is subject to the Employee Retirement Income Security Act of 1974, as amended (“ERISA”). Participants may elect to make tax deferred contributions ranging from 1% up to the lesser of 50% of their eligible compensation or $16,500. The $16,500 limit may be adjusted in future years by the Internal Revenue Service (“IRS”). The sum of the tax deferred contributions and the after-tax contributions cannot exceed 50% of the participant’s eligible compensation. Subject to limitation, the Company will make matching contributions in an amount equal to 50% of a participant’s total monthly contributions up to a maximum of 3% of their compensation. Also, the Company may, at the Board of Directors’ discretion, make a discretionary contribution to the Plan provided certain predetermined profit levels are attained.
		Effective August 1, 2009, the Company suspended employer matching and discretionary contributions; accordingly, no discretionary contributions were made for the Plan’s fiscal year ended December 29, 2009. Discretionary contributions of $8,803,031 were made for the Plan’s fiscal year ended December 29, 2008. Effective January 1, 2010, the Company reinstated employer matching and discretionary contributions that had been suspended since August 1, 2009 with the exception of a certain group of employees comprised of corporate officers and others.
		The Plan includes a negative enrollment policy. Under this policy, if an individual does not submit an automatic enrollment waiver or elect a deferral rate, the employee will be automatically enrolled in the Plan at a 3% deferral rate. The deferral rate is increased by 1% each September 1 until the deferral rate equals 6%.
		Participants who have attained age 50 before the close of the plan year are eligible to make catch-up contributions in addition to pre-tax contributions. A catch-up contribution is a pre-tax contribution that exceeds the annual deferral limit. A participant’s total catch-up contribution cannot exceed $5,500 in 2009 and $5,000 in 2008. The catch up contribution limits are determined by the IRS and then indexed for inflation. In addition to cash, in-kind contributions are permitted which may consist of stocks, bonds, property or other securities.

WESCO Distribution, Inc.
Retirement Savings Plan
Notes to Financial Statements
December 29, 2009 and 2008

		Vesting
		Participants are fully vested in the value of their contributions and related investment income at all times and vest in their allocated share of employer matching and discretionary contributions according to the following table:

Less than two years of service			0	%
Two years of service			20	%
Three years of service			40	%
Four years of service			66	%
Five or more years of service			100	%

		In conjunction with a leveraged recapitalization of the Company, all active employees as of June 5, 1998 became fully vested.
		Forfeitures
		Employer contributions forfeited by participants not vested at their termination date are used to reinstate previously forfeited account balances of former participants who have returned to the Company, reduce employer contributions in accordance with the Plan’s provisions or pay Plan expenses. Total forfeitures that reduced employer contributions in both 2009 and 2008 were approximately $1,099,000. As of December 29, 2009, a balance of approximately $649,000 was available to reduce employer contributions in 2010.
		Participant Accounts
		An account is maintained for each participant, which is credited with the participant’s and the employer’s matching contributions and an allocation of employer’s discretionary contributions, plan earnings and administrative expenses. Allocations are based on participant contributions or account balances, as defined by the Plan. The benefit to which a participant is entitled is the benefit that can be provided from the participant’s vested account balance.

2.		Summary of Significant Accounting Policies
		Accounting Principles
		The financial statements of the Plan have been prepared in accordance with accounting principles generally accepted in the United States of America. The following are the significant accounting policies followed by the Plan:
		Basis of Accounting
		The accounting records of the Plan are maintained on the accrual basis of accounting.
		Investment Valuation and Income Recognition
		The Plan has adopted a framework for measuring fair value under current accounting pronouncements that requires fair value measurements and enhanced disclosures about fair value measurements. This framework defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction. Disclosures include a fair value hierarchy which requires an entity to maximize the use of observable inputs when measuring fair value.

WESCO Distribution, Inc.
Retirement Savings Plan
Notes to Financial Statements
December 29, 2009 and 2008

The three levels of inputs that may be used to measure fair value are as follows:

	•		Level 1 – Observable inputs such as quoted prices in active markets for identical investments that the Plan has the ability to access.
	•		Level 2 – Inputs include:

	1.		Quoted prices for similar assets or liabilities in active markets;
	2.		Quoted prices for identical or similar assets or liabilities in inactive markets;
	3.		Inputs, other than quoted prices in active markets, that are observable either directly or indirectly;
	4.		Inputs that are derived principally from, or corroborated by, observable market data by correlation or other means.

•

Level 3 – Unobservable inputs in which there is little or no market activity for the asset or liability, which require the reporting entity to develop its own estimates and assumptions relating to the pricing of the asset or liability, including assumptions regarding risk.

		The asset’s or liability’s fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.
		Following is a description of the valuation methodologies used for assets measured at fair value. There have been no changes in the methodologies used as of December 29, 2009 and 2008.

	•		Common stocks, corporate bonds and U.S. government securities are valued at the closing price reported on the active market on which the individual securities are traded.
	•		Registered investment companies are valued at the net asset value of shares held by the Plan as of December 29.
	•		Common collective trusts are valued at fair value by determining the price of the underlying investments. Equities listed on an exchange are valued at the latest quoted sales price of the exchange on which the security is primarily traded. Securities that are not traded on the valuation date or securities that are not listed on an exchange are valued at the latest bid price provided by the trust’s pricing service.
	•		The Stable Value Fund (Note 7) is valued based on the underlying securities which include corporate bonds, commercial mortgage-backed securities and government securities.
	•		The RAFI Enhanced Large Company Fund is valued based on the underlying securities which include common stocks.
	•		Participant loans are valued at cost, which approximates fair value.

The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Plan believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement as of the reporting date.

WESCO Distribution, Inc.
Retirement Savings Plan
Notes to Financial Statements
December 29, 2009 and 2008

		Investment contracts held by a defined-contribution plan are required to be reported at fair value. However, contract value is the relevant measurement attribute for that portion of the net assets available for benefits of a defined-contribution plan attributable to fully benefit-responsive investment contracts, because contract value is the amount participants would receive if they were to initiate permitted transactions under the terms of the plan. As required by current accounting pronouncements, the statement of net assets available for benefits presents the fair value of the investment contracts as well as the adjustment of the fully benefit-responsive investment contracts from fair value to contract value. The statement of changes in net assets available for benefits is prepared on a contract value basis.
		Purchases and sales of securities are recorded on a trade date basis. Dividends are recorded on the ex-dividend date. Interest income is recorded on an accrual basis.
		Net Appreciation (Depreciation) in Value of Investments
		The Plan presents in the statement of changes in net assets available for benefits the net appreciation (depreciation) in the fair value of its investments, consisting of realized gains (losses) and unrealized gains (losses) in the registered investment companies, common collective trusts, Stable Value Fund, RAFI Enhanced Large Company Fund, WESCO International stock and other common stocks.
		Use of Estimates
		The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make significant estimates and assumptions. These estimates may affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of additions and deductions during the reporting period. Actual results could differ from those estimates.
		Risks and Uncertainties
		The Plan provides for various investment options in any combination of stocks, bonds, fixed income securities and other investment securities. Investment securities are exposed to various risks, such as interest rate, market and credit risk. Due to the level of risk associated with certain investment securities and the level of uncertainty related to changes in the value of investment securities, it is at least reasonably possible that changes in the near-term could materially affect (i) participants’ account balances, and (ii) the amounts reported in the (a) statements of net assets available for benefits and the (b) statements of changes in net assets available for benefits.
		Other
		All administrative expenses were paid by the Plan during 2009 and 2008.
		Payment of Benefits
		Benefits are recorded when paid.
		Subsequent Events
		Management evaluated subsequent events and transactions for potential recognition or disclosure in the financial statements through June 28, 2010, the day the financial statements were approved and authorized for use.

WESCO Distribution, Inc.
Retirement Savings Plan
Notes to Financial Statements
December 29, 2009 and 2008

3.		Tax Status
		The IRS has determined and informed the Company by a letter dated October 15, 2003, that the Plan is designed in accordance with Section 401(a) of the Internal Revenue Code (“IRC”) and, therefore, is exempt from federal taxes under provisions of Section 501(a). Accordingly, no provision for income taxes has been included in the Plan’s financial statements. The Plan has been amended since receiving its determination letter. However, the Plan administrator and the Plan’s tax counsel believe the Plan is designed and is currently being operated in compliance with the applicable requirements of the IRC.
4.		Investments
		The following tables set forth the fair value of the Plan’s assets by level, as described in Note 2, as of December 29, 2009 and 2008:

		December 29, 2009
		Level 1				Level 2				Level 3				Total
Shares of registered investment companies		$	177,568,193			$	—			$	—			$	177,568,193
Common collective trusts			—				20,074,381				—				20,074,381
Stock funds and self-directed accounts			15,724,184				—				—				15,724,184
Stable Value Fund			—				109,219,294				—				109,219,294
RAFI Enhanced Large Company Fund			—				20,946,580				—				20,946,580
Participant loans			—				—				9,154,053				9,154,053
		$	193,292,377			$	150,240,255			$	9,154,053			$	352,686,685

		December 29, 2008
		Level 1				Level 2				Level 3				Total
Shares of registered investment companies		$	124,263,627			$	—			$	—			$	124,263,627
Common collective trusts			—				14,054,450				—				14,054,450
Stock funds and self-directed accounts			11,463,975				—				—				11,463,975
Stable Value Fund			—				105,930,357				—				105,930,357
RAFI Enhanced Large Company Fund			—				17,744,056				—				17,744,056
Participant loans			—				—				7,280,126				7,280,126
		$	135,727,602			$	137,728,863			$	7,280,126			$	280,736,591

WESCO Distribution, Inc.
Retirement Savings Plan
Notes to Financial Statements
December 29, 2009 and 2008

The table below sets forth a summary of changes in the fair value of the Plan’s level 3 assets for the fiscal year ended December 29, 2009 and 2008:

		Participant Loans
		2009				2008
Balance, beginning of year		$	7,280,126			$	6,377,189
Purchases, sales, issuances and settlements, net			1,873,927				902,937
Balance, end of year		$	9,154,053			$	7,280,126

Investments (at fair value) representing 5% or more of the net assets available for benefits as of December 29, 2009 and 2008 were as follows:

		2009				2008
AMCAP Fund (Class R-4)		$	32,383,031			$	22,432,077
American Balanced Fund (Class A)			38,040,908				27,656,522
Columbia Acorn Fund (Class A)			26,925,313				18,503,267
RiverSource Midcap Value Fund *			18,139,384				—
Stable Value Fund			109,219,294				105,930,357
Thornburg International Value Fund			22,944,653				16,854,808

5.		Participant Loans
		Participants are permitted to borrow against a portion of their vested account balance, pursuant to nondiscriminatory rules established by the Administrative Committee, up to a maximum of $50,000 or 50% of their vested account balance. Each loan is to be repaid over a period not to exceed five years.
		The interest rate applied to participant loans is established each month by the Administrative Committee at 1% above the PNC Bank prime interest rate. The interest rate on loans outstanding ranged between 4.25% and 10.0% for the fiscal year ended December 29, 2009 and 5.0% and 10.0% for the fiscal year ended December 29, 2008. Principal and interest payments are generally made through monthly payroll deductions and are credited to the participant’s individual account. Loans of approximately $5,965,000 and $4,274,000 were made from the Plan and loan principal repayments of approximately $4,028,000 and $3,264,000 were received by the Plan for the fiscal years ended December 29, 2009 and 2008, respectively. Interest on the loans of approximately $501,000 and $530,000 was earned by the Plan for the fiscal years ended December 29, 2009 and 2008, respectively.

6.		Plan Termination
		Although the Company has not expressed any intent to do so, it has the right under the Plan to discontinue its contributions at any time and to terminate the Plan subject to the provisions of ERISA. In the event the Plan terminates, participants will become 100% vested in their accounts, and all vested assets shall be distributed to the participants in accordance with the terms of the Plan, or in such other manner, not inconsistent with the requirements of any applicable law or regulation, as the Company may in its sole discretion determine.
7.		The Stable Value Fund
		During 2007, the Plan began investing in a fully benefit-responsive synthetic guaranteed interest contract (“GIC”) with an insurance company as part of offering the Stable Value Fund (the “Fund”) investment option to participants. Contributions to this Fund are used to purchase units of a collective trust vehicle which is invested in high-quality U.S. bonds, including U.S. government treasuries, corporate debt securities, and other high-credit-quality asset-backed securities. The GIC issuer is contractually obligated to repay the principal and a specified interest rate that is guaranteed to the Plan. There are no reserves against contact value for credit risk of the contract issuer or otherwise.
		The Fund has entered into a wrap contract with an insurance company under which the insurance company provides a guarantee with respect to the availability of funds to make distributions from this investment option. This insurance contract is carried at contract value in the participants’ accounts.
		Participant accounts in the Fund are credited with interest at a fixed rate that is reset quarterly based on an agreed-upon formula as defined in the contract. The primary variables which could impact the future interest rates that are credited to the participant’s accounts (“credited rates”) include (i) the amount and timing of participant contributions, (ii) transfers and withdrawals into/out of the contract, (iii) the current yield of the assets underlying the contract, (iv) the duration of the assets underlying the contract, and (v) the existing difference between fair value of the securities and the contract value of the assets within the insurance contract. The credited rate of security-backed contracts will track current market yields on a trailing basis. The rate reset feature allows the contract value to converge with the fair value of the underlying portfolio over time, assuming the portfolio continues to earn the current yield for a period of time equal to the current portfolio duration.
		To the extent that the underlying portfolio has unrealized and/or realized losses, a positive adjustment is made when reconciling from fair value to contract value under contract value accounting. As a result, the future credited rate may be lower over time than the current market rates. Similarly, if the underlying portfolio generates unrealized and/or realized gains, a negative adjustment is made when reconciling from fair value to contract value, and in the future, the credited rate may be higher than the current market rates. The insurance contract cannot credit an interest rate that is less than zero percent.

WESCO Distribution, Inc.
Retirement Savings Plan
Notes to Financial Statements
December 29, 2009 and 2008

		Certain events limit the ability of the Plan to transact at contract value with the insurance company. Such events are limited to premature termination of the contract by the Plan or plan termination. The plan sponsor has not expressed any intention to take either of these actions.
		As described in Note 2, because the synthetic GIC is fully benefit-responsive, contract value is the relevant measurement attribute for that portion of the net assets available for benefits attributable to the synthetic GICs. Participants may ordinarily direct the withdrawal or transfer of all or a portion of their investment at contract value. The average yields earned by the Fund as of December 29, 2009 and 2008 are as follows:

Average yield for synthetic GICs		2009				2008
Based on actual earnings			3.47	%			4.39	%
Based on interest rate credited to participants			4.67	%			4.59	%

8.		Related Party Transactions
		Participants of the Plan may elect to invest in WESCO International, Inc. common stock within the WESCO Pooled Stock Fund. WESCO International, Inc. owns 100% of the Company. Therefore, these transactions qualify as party-in-interest transactions. Purchases and sales proceeds within the WESCO Pooled Stock Fund for 2009 were $2,754,000 and $3,086,000, respectively, and purchases and sales proceeds for 2008 were $4,414,000 and $2,305,000, respectively.
9.		Reconciliation of Financial Statements to Schedule H of form 5500
		The adjustment from fair value to contract value for fully benefit-responsive investment contracts is not recorded on Schedule H of Form 5500 at December 29, 2008.
		The following is a reconciliation of net assets available for plan benefits per the financial statements at December 29, 2008 to Form 5500:

		2008
Net assets available for plan benefits per the financial statements		$	288,168,853
Add: Adjustment from contract value for interest in Stable Value Fund relating to fully benefit responsive investment contracts			2,617,033
Net assets available for plan benefits per Schedule H of Form 5500		$	290,785,886

The following is a reconciliation of net appreciation (depreciation), interest, and dividends in fair value of investments per the financial statements for the years ended December 29, 2009 and 2008 to Schedule H of Form 5500:

		2009				2008
Net appreciation (depreciation), interest, and dividends per the financial statements		$	69,392,503			$	(101,895,563	)
Add: Adjustment from contract value for interest in Stable Value Fund relating to fully benefit responsive investment contracts			(2,617,033	)			933,595
Net appreciation (depreciation), interest, and dividends per Schedule H of Form 5500		$	66,775,470			$	(100,961,968	)

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		Alger Institutional Funds		Alger Midcap Growth Institutional Fund		$	9,610,149
		AMCAP Fund		AMCAP Fund (Class R-4)			32,383,031
		American Funds		American Balanced Fund (Class A)			38,040,908
		Columbia Mutual Funds		Columbia Acorn Fund (Class A)			26,925,313
		Loomis Sayles		Loomis Sayles Invest Grade Bond			16,813,799
		MFS Family of Funds		MFS Value Fund (Class A)			12,710,956
		RiverSource Trust		Midcap Value Fund Class R4			18,139,384
		Thornburg International		Thornburg International Value Fund			22,944,653
		Registered Investment Companies Total					177,568,193
		Manning & Napier Promix Funds		Manning & Napier Promix Conservative Trust			3,981,272
		Manning & Napier Promix Funds		Manning & Napier Promix Extended Trust			4,889,743
		Manning & Napier Promix Funds		Manning &Napier Promix Maximum Trust			7,373,154
		Manning & Napier Promix Funds		Manning & Napier Promix Moderate Trust			3,830,212
		Common Collective Trusts Total					20,074,381
*		WESCO International, Inc.		WESCO International Pooled Stock Fund			8,475,131
		3M Company		Common Stock			14,807
		Ameriprise Cash		Cash and cash equivalents			(46	)
		ABB Ltd Adr		Common Stock			12,698
		Abitibibowater Inc		Common Stock			643
		Acorda Therapeutics Inc.		Common Stock			1,270
		ADR Cemex		Common Stock			12,636
		Advanced Battery Technologies Inc.		Common Stock			5,835
		Advanced Energy Industries		Common Stock			3,363
		AGL Resources		Common Stock			37,090
		Aimco		Common Stock			5,611
		Alcatel-Lucent Ads		Common Stock			191
		Alcoa Inc.		Common Stock			16,416
		Allos Therapeutics Inc.		Common Stock			3,250
		Alpine Total Dynamic Dividend Fund		Closed-end Fund			349,390
		Altria Group Inc.		Common Stock			993
		Ambac Financial Group		Common Stock			2,520
		American Beacon Funds		Large Cap Value Fund			6,332
		American Century Funds		Diversified Bond Fund			296,883
		American Century Funds		Ginne Mae Fund			107,171
		American Century Funds		International Bond Fund			15,775
		American Semiconductor Group		Common Stock			4,199
		Anadarko Petroleum Corp.		Common Stock			6,400
		AOL Inc.		Common Stock			1,513
		Apache Corp.		Common Stock			10,452
		Apple Inc.		Common Stock			103,505
		Applied Materials		Common Stock			1,333
		Arcadia Resources, Inc.		Common Stock			409

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		Artisan Funds		International Investor Shrs			5,484
		AT&T Inc		Common Stock			3,020
		Atlas Pipeline Partners LP		Common Stock			239
		Authentec Inc		Common Stock			6,944
		Azteca Gold Corp		Common Stock			1,151
		B & G Foods Inc.		Common Stock			36,336
		Baidu.com Inc.		Common Stock			148,549
		Bank America Corp		Common Stock			1,512
		Barclays Bank Plc		Common Stock			4,230
		Bebida Beverage Co		Common Stock			1
		Bemis Co		Common Stock			8,576
		Berkshire Hathaway Inc.		Common Stock			9,840
		Bhp Billiton Ltp-Spon Adr		Common Stock			7,635
		Biogen Idec Inc.		Common Stock			1,335
		Biotime Inc.		Common Stock			119
		Boeing Co.		Common Stock			11,042
		BP Plc		Common Stock			17,846
		Bucyrus International Inc.		Common Stock			152,578
		Budget Group Inc.		Common Stock			13
		Buffalo		Small Cap Fund			11,960
		Burlington Northern Inc		Common Stock			1,969
		By Prudhoe Bay Royalty Trust		Common Stock			3,265
		CanWest Petroleum Inc.		Common Stock			3,570
		Cardium Therapeutics Inc.		Common Stock			4,770
		Caterpillar Inc.		Common Stock			28,815
		CBS Corp. Class B		Common Stock			57,013
		Cef Select Sector SPDR		Common Stock			38,934
		Celgene Corp.		Common Stock			16,836
		Cell Therapeutics		Common Stock			3,510
		Cheniere Energy Inc		Common Stock			516
		Chesapeake Energy		Common Stock			9,356
		Chevron Corp.		Common Stock			7,721
		Chicago Bridge & Iron Co.		Common Stock			5,470
		Cinemark Holdings Inc.		Common Stock			2,856
		Circuit City Stores		Common Stock			6
		Citigroup Inc.		Common Stock			17,019
		Clean Energy Fuels Corp.		Common Stock			3,883
		Clinical Data Inc.		Common Stock			4,892
		Compass Minerals International		Common Stock			17,088
		Coronado Res LTD		Common Stock			4,477
		Corporate Exec Board		Common Stock			2,326
		Costco Whsl Corp. New		Common Stock			6,448
		CrossTex Energy Inc		Common Stock			1,866
		Crowflight Minerals Inc.		Common Stock			149
		CSR PLC Cambridge		Common Stock			925
		CTS Corp.		Common Stock			956

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		Cubist Pharmaceuticals		Common Stock			3,826
		Deere & Co		Common Stock			7,251
		Del Global Technologies Corp.		Common Stock			60
		Deliste Incorporated		Common Stock			2
		Delta Petroleum Corp.		Common Stock			2,380
		Diamond Offshore Drilling		Common Stock			10,040
		Diana Shipping Inc.		Common Stock			7,445
		Discovery Laboratories Inc.		Common Stock			1,890
		Dodge & Cox Funds		Balanced Fund			137,628
		Dodge & Cox Funds		Income Fund			75,555
		Dodge & Cox Funds		Stock Fund			75,591
		Dorchester Minerals LP		Common Stock			2,153
		Dow Chemical		Common Stock			11,775
		Duluth Metals LTD		Common Stock			7,134
		Duoyuan Global Water Inc. Sponsored ADR		Common Stock			23,019
		Dynamic Materials Corp.		Common Stock			1,820
		E Trade Financial Corp.		Common Stock			8,850
		Eaton Corp.		Common Stock			46,422
		Energy Transfer Equity LP		Common Stock			6,337
		Energy Transfer Patners LP		Common Stock			10,561
		Enterprise Product Partners		Common Stock			9,459
		EON AG.SP ADR		Common Stock			14,072
		Excellon Resources Inc.		Common Stock			2,557
		Excelsior Funds		Value & Restructuring Fund			11,518
		Exide Technologies		Common Stock			36,250
		Exxon Mobil Corp.		Common Stock			21,685
		Fastenal Company		Common Stock			8,396
		Federal Mogul Corp.		Common Stock			1
		Fibertower Corp.		Common Stock			2,484
		First Horizon National Corp		Common Stock			4,086
		First Niagara Financial Group		Common Stock			4,265
		Flowserve Corp		Common Stock			9,666
		Federal Mogul Corp.		Series D Convertible Class A Preferred Stock			136
		Ford Motor Company		Common Stock			5,055
		Forest Labs		Common Stock			9,741
		Fortescue Metal Group LTD		Common Stock			584
		Fortum Corporation		Common Stock			18,633
		Franconia Minerals Corp.		Common Stock			1,191
		Freeport McMoran Copper & Gold Inc.		Common Stock			8,109
		Fuel Systems Solutions		Common Stock			12,684
		Fuel-Tech		Common Stock			3,830
		Gamco International Growth AAA		Foreign Large Growth Fund			16,180
		General Electric		Common Stock			164,920
		General Money Market Fund Inc. Class A		General Money Market Fund			1,022,550
		Genzyme Corp.		Common Stock			4,981
		GMX Resources Inc.		Common Stock			7,025

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		Goldcorp Inc.		Common Stock			3,951
		Goldman Sachs Group		Common Stock			32,824
		Harbor Funds		International Fund			45,060
		Harbor Funds		Bond Fund — Institutional Class			11,599
		Hawaiian Electric Ind. Inc.		Common Stock			23,229
		Headwaters Inc.		Common Stock			2,372
		Heartland Funds		Select Value Fund			22,488
		Hewlett Packard		Common Stock			21,028
		Honeywell Intl Inc.		Common Stock			26,121
		Huntington Bancshare		Common Stock			1,115
		I Shares		Silver Trust			7,565
		I Shares		TR JBOXX High Yield Corporate Bond Fund			2,620
		I Shares		S&P Global Telecom Fund			10,998
		I Shares		DJ Select Dividend Index Fund			8,026
		I Shares		S&P Global 100			4,876
		I Shares		S&P Gloal Finl Sector			5,011
		I Shares		DJ U.S. Consumer Cycl SEC Fund			2,812
		I Shares		TR Dow Jones US Aerospace & Defense Equity Fund			7,755
		Icon Funds		Icon Healthcare Fund			43,927
		Icon Funds		International Equity Fund			36,906
		IGO Inc.		Common Stock			14,160
		Integral Technologies Inc.		Common Stock			3,933
		Intel Corp.		Common Stock			22,442
		International Pkg & Logistics		Common Stock			2
		Interplay Entertainment		Common Stock			55
		Intl Speedway		Common Stock			8,162
		Intuitive Surgical Inc.		Common Stock			30,658
		Invio Biomedical Corp.		Common Stock			1,740
		Ivanhoe Energy, Inc.		Common Stock			303
		J.P. Morgan Chase & Co.		Common Stock			18,671
		Janus Funds		Global Technology Fund			13,060
		Janus Funds		Overseas Fund			128,828
		Janus Funds		Mid Cap Value Fund			24,230
		Janus Funds		Enterprise Fund			19,891
		Janus Funds		Special Equity Fund			12,943
		Janus Funds		Orion Fund			10,350
		Johnson & Johnson		Common Stock			5,390
		Joy Global Inc.		Common Stock			7,850
		Keryx Biopharmaceuticals		Common Stock			466
		Kinder Morgan Energy Partners LP		Common Stock			15,173
		Klondike Silver Corp.		Common Stock			2
		Koko Petroleum Inc.		Common Stock			12
		Kona Grill Inc.		Common Stock			637
		Kraft Foods		Common Stock			933
		Las Vegas Sands Corp.		Common Stock			7,645

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		Lehman Brothers Holdings Inc		Preferred Stock			52
		Lowes Companies		Common Stock			7,083
		Managers Intermediate Duration Govt		Fixed Fund			47,743
		Manhattan Pharmaceuticals		Common Stock			312
		Manitowoc Inc.		Common Stock			22,658
		Mannkind Corp		Common Stock			3,404
		Marisco		21st Century Mutual Fund			6,756
		Marsico		Large Growth Fund			23,251
		Market Vectors ETF TR		Agribusiness Fund			6,518
		Market Vectors ETF TR		Global Alternative Energy Fund			3,755
		Masco Corp		Common Stock			42,030
		Matrix Advisors		Value Fund			39,201
		Maxwell Technologies Inc		Common Stock			701
		MBIA Inc.		Common Stock			12,180
		MDRNA Inc.		Common Stock			164
		Medoro Res LTD		Common Stock			2,320
		Merck & Co.		Common Stock			8,719
		Metalico Inc.		Common Stock			1,723
		Microsoft Corp.		Common Stock			31,439
		Mosaic Co.		Common Stock			2,924
		Myriad Pharmaceuticals Inc.		Common Stock			1,566
		Nacel Energy Corp.		Common Stock			1,740
		Neomedia Technologies		Common Stock			110
		Nestle SA Sponsored ADR		Common Stock			19,172
		Netlist Inc.		Common Stock			2,700
		Neuberger Berman		Real Estate Fund			14,734
		Newcastle Investment Corp.		Common Stock			399
		Nokia Corp.		Common Stock			5,415
		Nordic American		Common Stock			6,030
		Northern Funds		High Yield Fixed Income Fund			11,050
		Nucor Corp		Common Stock			9,212
		Nvdia Corp		Common Stock			2,703
		Oakmark Funds		Global Fund			50,367
		Oakmark Funds		Mutual Fund			13,242
		Oakmark Funds		Oakmark Equity and Income Fund (I)			37,941
		Oakmark Funds		International Fund (Class I)			11,032
		Oneok Partners LP		Common Stock			9,384
		Oracle Systems		Common Stock			7,503
		Oshkosh Corporation		Common Stock			12,194
		Palomar Medical Tech		Common Stock			18,940
		Parnassus Income Trust		Equity Income Fund			50,386
		Paychex Inc.		Common Stock			4,644
		Peabody Energy Corp		Common Stock			3,922
		Petroquest Energy Inc.		Common Stock			3,155
		Petroleo Brasileiro SA Petrobas Sponsored ADR		Common Stock			23,383
		Pfizer Inc.		Common Stock			3,924

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		Philip Morris International Inc.		Common Stock			2,443
		PIMCO Funds		Real Return Fund			9,672
		PNC Financial Services Group		Common Stock			1,490
		PNM Resources Inc.		Common Stock			57,060
		Polymet Mining Corp.		Common Stock			15,211
		Potash Corp of Saskatchewan		Common Stock			32,878
		Powershares		Agricultural Fund			18,972
		Powershares		DB Multi Sector Commodity TR			75,049
		Powershares		Global Water Portfolio Fund			10,265
		Precision Castparts		Common Stock			8,443
		Prestige Brand Holdings		Common Stock			6,424
		Proshares TR		Ultra Financial Fund			194,621
		Qualcomm Inc.		Common Stock			2,333
		Range Resources Corp.		Common Stock			5,108
		Rayonier Inc		Common Stock			853
		Research In Motion LTD		Common Stock			10,797
		Reserve Primary Fund		Primary Fund			46,767
		RF Micro-Devices		Common Stock			14,610
		Rino International Corporation		Common Stock			2,820
		Royce		Total Return Fund			6,202
		RRI Energy Inc.		Common Stock			8,820
		RS Partners		Growth Fund			3,849
		RVS		Mid Cap Growth Fund			80,382
		Riversource Trust		Diversified Bond Class R4 Fund			84,968
		Riversource Trust		High Yield Class R4 Bond Fund			56,039
		Sasol LTD ADR		Common Stock			23,109
		Seligman		Global Technology Fund			94,463
		Sequenom Inc.		Common Stock			170
		Short QQQ		Equity Fund			13,029
		Silver Grail Res LTD		Common Stock			2,716
		Silver Star Energy		Common Stock			3
		Sirius Satellite Radio Inc.		Common Stock			355
		SIT Funds		US Government Securities Fund			170,314
		Sound Shore Fund		Common Stock			5,805
		SPDR		Series Trust Fund			63,498
		Spectra Energy Corp.		Common Stock			5,140
		SSGA		International Stock Selection Fund			42,395
		Statiol ASA Group		Common Stock			20,590
		Strategic Resource Acquisition Corp		Common Stock			314
		Sun Microsystems		Common Stock			159
		Sysco Corp.		Common Stock			6,660
		T. Rowe Price Funds		Balanced Fund			95,419
		T. Rowe Price Funds		Capital Appreciation Fund			119,794
		T. Rowe Price Funds		New Era Fund			109,462
		T. Rowe Price Funds		Growth Stock Fund			45,752
		T. Rowe Price Funds		Spectrum International Fund			15,973

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		T. Rowe Price Funds		Dividend Growth Fund			4,644
		TCW Funds, Inc.		Focused Equities Fund			13,651
		Terra Nitrogen Company		Common Stock			10,475
		Teton Energy Corp.		Common Stock			60
		The India Fund Inc.		Equity Fund			11,605
		The Muhlenkamp Fund		Equity Fund			7,306
		Third Avenue		Real Estate Value Fund			4,789
		Third Avenue		International Value Fund			53,130
		Third Avenue		Value Fund			16,199
		Third Avenue		Small Cap Value Fund			27,002
		Thompson Plumb and Associates		Growth Fund			3,897
		Threadneedle		Emerging Markets Fund			51,132
		Time Warner Cable Inc.		Common Stock			35,684
		Time Warner Inc.		Common Stock			20,586
		Titanium Metals Corp.		Common Stock			7,428
		Transocean Inc.		Common Stock			16,726
		Trinity Industries Inc.		Common Stock			3,641
		Tumi Res LTD		Common Stock			1,783
		TVIA Inc.		Common Stock			21,500
		UIL Holdings Corp		Common Stock			28,630
		Ultra Petroleum Corp.		Common Stock			10,230
		Ultrashort Financial		Exchange Traded Fund			96,120
		Ultrashort QQQ		Exchange Traded Fund			56,520
		Unigene Labs Inc.		Common Stock			4,608
		US Bancorp		Common Stock			8,956
		Valeant Pharmaceuticals Intl.		Common Stock			3,217
		Vanguard Funds		Specialized Portfolios - Dividend Appreciation			18,948
		Vanguard Funds		Windsor II Fund			45,745
		Vanguard Funds		Wellesley Income Fund			24,407
		Vanguard Funds		International Value Fund			21,144
		Vanguard Funds		International Growth Fund			21,825
		Vecima Networks Inc		Common Stock			5
		Veolia Environment ADR		Common Stock			4,979
		Verizon Communications		Common Stock			3,343
		Viacom Inc.		Common Stock Class B			112,672
		Walgreen Co		Common Stock			7,446
		Wasatch Heritage Growth Fund		Growth Fund			10,165
		Washington Mutual Savings Bank		Common Stock			13,514
		Wells Fargo & Co		Common Stock			10,672
		White Mountains Insurance Group		Common Stock			3,641
		Windstream Corp		Common Stock			33,300
		Wynn Resorts, Limited		Common Stock			5,893
		Yara International ASA Sponsored ADR		Common Stock			11,557
		Stock Funds and Self-Directed
		Accounts Total					15,724,184

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		Institutional Enhanced Index Fixed
		Income Fund		Common Collective Trust			109,219,294
		Wrapper Contract		Wrapper Contract			—
		Stable Value Fund Total					109,219,294
		EVERGREEN INST MONEY MARKET FUND CL I (FD #495)		Cash and Cash Equivalents			378,580
		3M CO COM		Common Stock			76,053
		ABBOTT LABS COM		Common Stock			63,430
		ABERCROMBIE & FITCH CO CL A		Common Stock			6,392
		ABM INDS INC COM		Common Stock			2,974
		ACCENTURE LTD COM		Common Stock			47,477
		ACTUANT CORP COM		Common Stock			2,656
		ACUITY BRANDS INC COM		Common Stock			4,189
		ADOBE SYS INC COM		Common Stock			8,074
		ADVANCE AUTO PARTS COM		Common Stock			5,951
		AECOM TECHNOLOGY CORP COM		Common Stock			4,054
		AES CORP COM		Common Stock			21,450
		AETNA INC COM		Common Stock			37,033
		AFFILIATED COMPUTER SVCS INC CL A		Common Stock			4,832
		AFFILIATED MANAGERS GROUP COM		Common Stock			3,306
		AFLAC INC COM		Common Stock			39,532
		AGCO CORP COM		Common Stock			10,685
		AGILENT TECHNOLOGIES INC COM		Common Stock			16,196
		AGL RES INC COM		Common Stock			5,378
		AIR PRODUCTS & CHEMICALS INC COM		Common Stock			14,056
		AIRCASTLE LTD COM		Common Stock			3,715
		AK STEEL HLDG CORP COM		Common Stock			14,646
		ALBEMARLE CORP COM		Common Stock			5,503
		ALBERTO-CULVER CO COM		Common Stock			4,213
		ALCOA INC COM		Common Stock			59,263
		ALEXANDER & BALDWIN INC COM		Common Stock			4,598
		ALEXANDRIA REAL ESTATE EQUITIES COM		Common Stock			5,528
		ALLEGHANY CORP DEL COM		Common Stock			5,174
		ALLEGHENY ENERGY INC COM		Common Stock			4,969
		ALLEGHENY TECHNOLOGIES INC COM		Common Stock			13,087
		ALLERGAN INC COM		Common Stock			6,425
		ALLIANCE RESOURCE PARTNERS LP COM		Common Stock			2,917
		ALLIANCEBERNSTEIN HOLDING LP		Common Stock			5,940
		ALLIANT ENERGY CORP COM		Common Stock			7,630
		ALLIANT TECHSYSTEMS INC COM		Common Stock			2,162
		ALLIED CAP CORP NEW COM		Common Stock			11,326
		ALLIED WORLD ASSURANCE HOLD COM		Common Stock			8,834
		ALLSTATE CORP COM		Common Stock			63,390
		ALTERA CORP COM		Common Stock			5,665

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i

(a)		(b)		(c)		(d)
				Description of Investment
		Identity of Issue,		Including Maturity Date,
		Borrower, Lessor or		Rate of Interest, Collateral,		Current
		Similar Party		Par, or Maturity Value		Value
		ALTRIA GROUP INC COM		Common Stock			149,312
		AMAZON COM INC COM		Common Stock			19,936
		AMERCO COM		Common Stock			5,911
		AMEREN CORP COM		Common Stock			33,912
		AMERICAN EAGLE OUTFITTERS INC NEW COM		Common Stock			7,353
		AMERICAN ELEC PWR CO INC COM		Common Stock			31,011
		AMERICAN EXPRESS COMPANY COM		Common Stock			103,181
		AMERICAN FINL GRP INC OHIO COM		Common Stock			13,796
		AMERICAN GREETINGS CORP CL A COM		Common Stock			4,382
		AMERICAN INTL GRP INC COM		Common Stock			15,513
		AMERICAN NATL INS CO COM		Common Stock			7,838
		AMERICAN TOWER CORP CL A		Common Stock			4,232
		AMERICAN WATER WORKS CO INC COM		Common Stock			4,988
		AMERIGAS PARTERNS LP UNIT LTD PARTNERSHIP		Common Stock			2,857
		AMERIGROUP CORPORATION COM		Common Stock			2,747
		AMERIPRISE FINANCIAL INC COM		Common Stock			17,026
		AMERISOURCEBERGEN CORP COM		Common Stock			58,594
		AMERISTAR CASINOS INC COM		Common Stock			1,650
		AMGEN INC COM		Common Stock			23,238
		AMKOR TECHNOLOGY INC COM		Common Stock			5,494
		AMPHENOL CORP NEW CL A		Common Stock			416
		AMR CORP DEL COM		Common Stock			25,035
		ANADARKO PETROLEUM CORP COM		Common Stock			45,376
		ANALOG DEVICES INC COM		Common Stock			10,082
		ANIXTER INTL INC COM		Common Stock			3,182
		ANNALY MTG MGMT INC COM		Common Stock			5,177
		ANNTAYLOR HLDGS INC COM		Common Stock			5,581
		AOL INC COM		Common Stock			8,348
		AON CORP COM		Common Stock			16,128
		APACHE CORP COM		Common Stock			33,028
		APARTMENT INVT & MGMT CO CL A		Common Stock			6,412
		APOLLO GRP INC CL A		Common Stock			4,515
		APPLE INC COM		Common Stock			83,222
		APPLIED INDL TECHNOLOGIES INC COM		Common Stock			2,322
		APPLIED MATERIALS INC COM		Common Stock			15,980
		APTARGROUP INC RST		Common Stock			4,436
		AQUA AMERICA INC		Common Stock			2,732
		ARCH CAPITAL GROUP LTD COM		Common Stock			18,183
		ARCH CHEMICALS INC COM		Common Stock			1,693
		ARCHER DANIELS MIDLAND CO COM		Common Stock			46,187
		ARKANSAS BEST CORP DEL COM		Common Stock			3,806
		ARMSTRONG WORLD INDUSTRIES COM		Common Stock			25,790
		ARROW ELECTRS INC COM		Common Stock			20,096
		ARTHUR J. GALLAGHER & CO COM		Common Stock			5,560
		ARVINMERITOR INC COM		Common Stock			28,856

WESCO Distribution, Inc.
Retirement Savings Plan
Schedule of Assets (Held at End of Year)
EIN 25-1723345, Plan Number 001
December 29, 2009		Schedule H, line 4i