* Big banks fall; weigh on financial sector
* JP Morgan down after signaling rough first quarter
* Indexes: Dow down 0.12 pct, S&P flat, Nasdaq up 0.64 pct (Updates to afternoon)
By Noel Randewich
Feb 24 (Reuters) - U.S. stocks were mixed on Wednesday as investors focused on banks' vulnerability to decade-low oil prices that have left energy companies struggling to pay their debts and a rise in Apple propped up the S&P 500.
Six of the 10 major S&P sectors were higher, with telecoms up 0.55 percent thanks to a 0.77 percent increase in AT&T.
The S&P financial sector, already the worst performing sector this year, fell 0.69 percent and was the biggest loser among the sectors.
Shares of Wells Fargo, JPMorgan, Goldman Sachs, Morgan Stanley and Citigroup were among the worst hit.
JPMorgan flagged declining investment banking revenue and raised its provisions for energy loan losses, while Morgan Stanley said most of its energy loans were to non-investment grade firms.
Crude prices near 2003 lows have hammered the earnings of U.S. energy companies, exacerbated fears of a slowing global economy and created turbulence on Wall Street that has left the S&P 500 almost 7 percent weaker since the start of the year.
"We had a nice rebound in stocks last week after a terrible January, and we're nearing the end of that bounce," said Mohannad Aama, managing director at Beam Capital Management in New York. "The general trend is down."
At 2:29 pm, the Dow Jones industrial average was down 0.12 percent at 16,411.38 and the S&P 500 was flat at 1,921.2.
The Nasdaq Composite added 0.43 percent to 4,522.90, helped by a 0.87 percent rise in Apple. Concerns about slowing iPhone sales had pushed Apple's stock down 19 percent in the past three months.
Boeing fell 1.65 percent after Goldman Sachs cut its price target on the stock.
Ford declined 3.3 percent and General Motors was off 2.3 percent after Credit Suisse said it was a "poor time" to own auto stocks.
Advancing issues outnumbered declining ones on the NYSE by 1,503 to 1,479. On the Nasdaq, 1,531 issues rose and 1,191 fell.
The S&P 500 index showed eight new 52-week highs and five new lows, while the Nasdaq recorded nine new highs and 90 lows. (Additional reporting by Abhiram Nandakumar in Bengaluru; Editing by Meredith Mazzilli)