Stock index futures fell slightly on Friday after Bank of America Corp reported a sharp drop in earnings, adding to investors' caution shortly after the start of the earnings season.

The largest U.S. bank reported a steeper-than-expected decline of 37.5 percent in profit and named a new chief financial officer. The stock, a Dow component, was volatile in premarket trading, falling by 1.7 percent before rebounding to turn positive.

Another major company to report was Google Inc , which worried investors late on Thursday with a large jump in first-quarter spending. But the company's finance chief said it was a sign of optimism. The Internet company reported an adjusted profit slightly under expectations, and the stock fell 5.4 percent to $547.04 in premarket trading.

Bank of America's results followed earnings from JPMorgan Chase & Co on Wednesday, which reported fewer outstanding loans and which raised questions about banks' future profitability.

When you looked at JPMorgan on Wednesday, as you read between the lines of where they get revenue, you saw some areas of concern and some warnings from them, Oliver Pursche, president at Gary Goldberg Financial Services in Suffern, New York.

Now we're seeing a similar breakdown in Bank of America, which reaffirms our position that financials will continue to be under some pressures.

The first week of earnings has been mixed, with bellwether companies unable to excite the market despite some cases of stronger-than-expected profits. Investors have been disappointed with companies' revenues or outlooks.

Mattel Inc reported on Friday first-quarter earnings that fell due to higher costs, though they met Wall Street's expectations.

Earnings season is starting out rather slow, though we're still optimistic on the season as a whole, Pursche said. But if across industries we start seeing more red flags ... that's when we'll become more bearish.

S&P 500 futures fell 2.7 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures fell 23 points and Nasdaq 100 futures fell 3.25 point.

March consumer price data will be released at 8:30 a.m. <1230 GMT> and will be examined for the impact of energy and food prices.

Although core inflation figures are expected to show the same gain as in February of 0.2 percent, any move higher could put pressure on the Federal Reserve's monetary policy.

In China, inflation jumped to a 32-month high, reinforcing the view that the government will have to do more to rein in prices.

The New York Fed's Empire State manufacturing index for April and the Thomson Reuters/University of Michigan consumer sentiment report will also be released, with manufacturing seen weakening and confidence expected to edge slightly higher from the previous month.

(Editing by Kenneth Barry)