U.S. stocks ended little changed on Thursday, with the Standard & Poor's 500 Index near a four-month high, as investors assessed earnings releases and data showing the labor market is improving with little pickup in inflation.

Banks rallied, with Bank of America Corp. advancing a fifth day after saying it sees more room for cost cuts. Airline operators jumped along with Delta Air Lines Inc., which posted quarterly earnings that beat projections. Technology shares retreated as Seagate Technology Plc plummeted 20 percent after reporting preliminary revenue that trailed estimates.

The S&P 500 added less than 0.1 percent to 2,082.78 at 4 p.m. in New York, after reaching the highest level since Dec. 4 yesterday. Financial shares and commodity producers have led the benchmark gauge to a 1.7 percent advance so far this week, after the measure faltered last week amid skepticism central banks' efforts to shore up growth will fail to be effective. The Dow Jones Industrial Average increased by 18 points to 17,926.43 on Thursday.

While the rally that lifted the S&P 500 since February is regaining momentum, skepticism still prevails, with valuations far above their five-year average and the seven-year bull market weeks away from becoming the second-longest in history. Some investors also attribute the rebound to short squeezes, with a Goldman Sachs Group Inc. gauge of the 50 most-shorted stocks posting its biggest two-day jump in almost two months.

Analysts have slashed profit estimates for S&P 500 members this year, now projecting net income fell 10 percent in the first quarter. Investors are also tracking economic releases. Stock futures climbed in pre-market trading after data showed initial jobless claims fell to match the lowest level since 1973 and the cost of living excluding food and fuel rose less than forecast in March.