US STOCKS-Markets advance as mergers, deals spur buying

* HP offer of $24 a share for 3PAR tops Dell bid

* Campbell may bid for United Biscuits: report

* 3M CEO says may double acquisition money spent in 2010

* Indexes up: Dow 0.5 pct, S&P 0.5 pct, Nasdaq 0.1 pct

* For up-to-the-minute market news see [STXNEWS/US]

(Updates to the open)

By Ryan Vlastelica

NEW YORK, Aug 23 (Reuters) - U.S. stocks rebounded from a two-week string of losses in the Dow and S&P on Monday as a bidding war involving HP and Dell, along with other acquisition deals, lifted sentiment.

In the past week's second major deal in the technology space, Hewlett-Packard Co bid $24 a share in cash for 3PAR Inc , topping an earlier bid from Dell Inc . Shares of 3PAR, a data storage company, surged 40 percent to $25.28, while Dow component HP slid edged 0.2 percent lower to $39.77. Dell shares were up 0.8 percent at $12.17. For details see [ID:nN23188685]

Last week Intel Corp moved to acquire software maker McAfee Inc for $7.7 billion. [ID:nN19252526]

"The fact that HP is topping a Dell offer suggests that companies are willing to pay for assets they think are strategic," said Jordan Posner, senior portfolio manager at the New York-based Matrix Asset Advisors.

The M&A activity "creates an opportunity for stocks to reflect some of the good fundamentals that are out there," Posner said.

Campbell Soup Co may make a $2.3 billion break-up bid for Britain's United Biscuits, which is owned by private equity firms PAI Partners and Blackstone Group LP , according to a report in the London-based Sunday Times. Campbell shares were up 0.8 percent to $36.95. [ID:nLDE67L05L]

3M Co's chief executive, George Buckley, said the Dow component may spend about $2 billion on acquisitions in 2010, twice its previous estimate. 3M shares gained 1.8 percent to $82.10. [ID:nTOE67M07U]

The Dow Jones industrial average <.DJI> was up 46.47 points, or 0.45 percent, at 10,260.09. The Standard & Poor's 500 Index <.SPX> was up 5.51 points, or 0.51 percent, at 1,077.20. The Nasdaq Composite Index <.IXIC> was up 3.07 points, or 0.14 percent, at 2,182.83.

Concerns about the strength of the recovery have intensified in recent weeks, with weak economic data adding to the cautious tone and depressing trading volume levels. Both the Dow and S&P have notched two straight weeks of losses

Thomas Hoenig, the Kansas City Reserve Bank President, is scheduled to speak later on Monday. Hoenig is a prominent hawk on the Fed and recently said that by keeping rates near zero for so long, the Fed was undertaking a "dangerous gamble." [ID:nN13260474]

October crude oil futures rose 0.2 percent to $73.95 per barrel, though prices were close to last week's six-week lows on bulging U.S. inventories. [ID:nSGE67M035]

The Federal Reserve plans to reduce American International Group Inc's credit line by about $3.6 billion in a sign of growing confidence that the government bailed-out insurer can emerge from taxpayer support, Bloomberg said, citing a person with knowledge of the proposal. [ID:nSGE67M06E]

AIG rose 1.8 percent to $35.80.

U.S. stocks slipped on Friday and the S&P 500 and Dow fell on persistent concerns the recovery has tapered off. For the week, the S&P 500 was down 0.7 percent and the Dow slipped 0.9 percent, while the Nasdaq gained 0.3 percent on some positive outlooks in technology shares. (Editing by Padraic Cassidy)