* Exxon, Chevron up slightly after results
* LinkedIn, Abbvie soar after results
* Keycorp down after agreeing to buy First Niagara
* Consumer spending barely rose in September
* Dow up 0.05 pct, S&P flat, Nasdaq up 0.03 pct (Updates to early afternoon)
By Abhiram Nandakumar
Oct 30 (Reuters) - U.S. stock indexes were flat on the last trading day of what could be the best month for stocks in four years as investors assessed consumer spending data and results from energy majors.
The S&P consumer staples sector slipped 0.63 percent after data showed U.S. consumer spending barely rose in September and the University of Michigan's index on consumer sentiment came in below expectations.
The three major indexes have rallied about 9 percent in October, mostly driven by the Fed's decision to keep rates unchanged at its September meeting and largely positive third-quarter results.
Energy majors Exxon and Chevron reported better-than-expected results, helped by strong refining margins. The stocks were up about 1 percent, with Chevron providing the biggest boost to the Dow.
"My expectation is that the rest of the day is going to be pretty quiet," said Bob Phillips, managing principal of Spectrum Management Group in Indianapolis.
At 12:51 p.m. ET (1651 GMT), the Dow Jones industrial average was up 8.92 points, or 0.05 percent, at 17,764.72, the S&P 500 was down 0.07 points at 2,089.34 and the Nasdaq Composite index was up 1.46 points, or 0.03 percent, at 5,075.74.
A 0.8 percent drop in the financials sector offset gains in energy stocks, which were lifted by higher crude prices.
As the earning season winds down, investors will be looking at data over the next several weeks for clues on the state of the economy before the Federal Reserve's December meeting.
The Fed made it clear on Wednesday that a rate hike in December was still possible if there was sufficient evidence that the economy could withstand an increase.
Abbvie was up 10.7 percent at $59.89, giving the biggest boost to the S&P 500, while CVS Health fell 3.9 percent to $99.74 after results.
Keycorp fell 6.7 percent to $12.49 after it said it would buy First Niagara Financial for $4.1 billion. First Niagara rose less than a percent.
Valeant Pharmaceuticals was down 11.7 percent at $98.46 after it said it was cutting all ties with specialty pharmacy Philidor.
LinkedIn shot up 11.4 percent to $241.81 while Expedia jumped 8.7 percent to $138.12 after their quarterly results beat estimates.
Baidu was up nearly 10 percent at $185.49 after strong results, providing the biggest boost to the Nasdaq.
Strong results from blue-chips have helped improve analyst sentiment on overall earnings.
Profits at S&P 500 companies are now expected to fall 1 percent, far less than the 4.9 percent forecast at the start of earnings season, according to Thomson Reuters data.
Advancing issues outnumbered decliners on the NYSE by 1,553 to 1,345. On the Nasdaq, 1,468 issues fell and 1,211 advanced.
The S&P 500 index showed 15 new 52-week highs and four new lows, while the Nasdaq recorded 38 new highs and 66 new lows. (Reporting by Abhiram Nandakumar in Bengaluru; Editing by Saumyadeb Chakrabarty)