Updated from 11:56 a.m. EDT

Shares of Harrah's Entertainment ( HET) were among the NYSE's winners Monday, jumping 14% after the casino operator said it received a buyout offer from private equity firms Texas Pacific Group and Apollo Management.

Harrah's said the firms offered to buy the company for $81 a share in cash. The company established a special committee to evaluate the proposal but noted that there is no assurance a deal will be reached. Shares recently were trading up $9.17 to $75.60.

Pacific Sunwear ( PSUN) shares climbed 8% after the casual-apparel retailer announced the resignation of its chief executive and backed its third-quarter earnings guidance. The company said that Seth Johnson will be replaced by board member Sally Frame Kasaks on an interim basis until the company finds a permanent CEO. Kasaks is a retail industry veteran, having served as the head of AnnTaylor ( ANN), Abercrombie & Fitch ( ANF) and Talbots ( TLB).

Pacific Sunwear also reported a 2.4% decline in September same-store sales and said it continues to expect third-quarter earnings, excluding items, of 22 cents to 30 cents a share. Shares were up $1.19 to $16.27.

Shares of Wal-Mart ( WMT) slipped 2% after the world's largest retailer reported September same-store sales data that was toward the bottom half of its earlier guidance. The company posted a same-store sales gain of 1.8%, compared with its earlier projection for a rise of 1% to 3%. Wal-Mart plans to issue its complete September results on Thursday. Shares were down 85 cents to $48.47.

Shares of Pier 1 Imports ( PIR) rose 4% after the retailer said that its CEO will retire at the end of February. The company said that it hired a search firm to find a replacement for Marvin Girouard. "I am grateful to the board for their support. I feel it is time for me to leave in the course of a normal retirement and allow new leadership to emerge and flourish," Girouard said in a statement. Shares of the retailer have fallen about 9% since the beginning of the year. The stock recently was up 26 cents to $7.68.

First Republic Bank ( FRC) slid 9% after the banking services company put third-quarter earnings lower than Wall Street's forecast. The company estimated third-quarter earnings of 56 cents to 58 cents a share, but the results will include federal and state tax benefits of 7 cents a share, the company said. Analysts polled by Thomson First Call project earnings of 62 cents a share.

"Third quarter earnings are impacted primarily by continuing net interest margin pressure due to the current interest rate environment and expansion expenses, including initial costs relating to the planned acquisition of Bank of Walnut Creek," First Republic said. Shares were trading down $3.78 to $38.78.

Shares of Western Union ( WU) rose 4% on their first day of trading. The money-transfer company was spun off from First Data ( FDC). On Friday, Western Union said its board approved a $1 billion stock repurchase plan. Shares of Western Union recently were up 90 cents to $20.03.

Shares of I-Flow ( IFLO) rose 11% after the company agreed to sell its InfuSystem unit to HAPC, a blank-check company, for $140 million. The cash portion of the deal will range from $65 million to $85 million, with the balance paid with a secured note. InfuSystem provides infusion pump management services to oncologists. I-Flow said the deal will enable it to concentrate on its ON-Q pain relief franchise. Shares were up $1.30 to $13.32.

The NYSE's other big volume leaders included Nortel Networks ( NT), down 3 cents to $2.27; Sprint Nextel ( S), down 15 cents to $17; Pfizer ( PFE), up 13 cents to $28.49; Advanced Micro Devices ( AMD), down 42 cents to $24.43; General Electric ( GE), up 28 cents to $35.58; Time Warner ( T), up 6 cents to $18.29; and Exxon Mobil ( XOM), up 10 cents to $67.20.

Nasdaq volume leaders included Sun Microsystems ( SUNW), up 5 cents to $5; Intel ( INTC), up 4 cents to $20.61; Sirius Satellite Radio ( SIRI), up 9 cents to $4.01; Oracle ( ORCL), up 7 cents to $17.81; Microsoft ( MSFT), up 4 cents to $27.39; Cisco Systems ( CSCO), up 18 cents to $23.16; and Apple Computer ( AAPL), down $2.33 to $74.65.

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