U.S. stock index futures were little changed on Tuesday after earnings from JPMorgan and Goldman Sachs, and ahead of testimony from U.S. Federal Reserve Chair Janet Yellen and results from Goldman Sachs.

Yellen is set to begin her semiannual testimony on the central bank's monetary policy before the Senate Banking Committee at 10:00 a.m. (1400 GMT). Investors will be closely monitoring for any indication on when the Fed plans to hike interest rates.

JPmorgan Chase (JPM) shares rose 1.4 percent to $57.08 in premarket trade after the biggest U.S. bank by assets reported second-quarter earnings.

Goldman Sachs (GS) shares advanced 2.4 percent to $170.99 before the opening bell after the bank posted its second-quarter results.

S&P 500 profits are seen growing 6.2 percent in the second quarter, according to Thomson Reuters data, down from the 8.4 percent growth forecast at the start of April. Revenue is seen up 3.1 percent. S&P 500 companies expected to report earnings after the close include Yahoo Inc (YHOO) and Intel Corp (INTC).

S&P 500 e-mini futures rose 1.5 points and fair value - a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract - indicated a flat open. Dow Jones industrial average e-mini futures rose 35 points and Nasdaq 100 e-mini futures added 6.75 points.

Investors will also grapple with a host of economic data on Tuesday, with June import prices, the July New York Fed manufacturing survey, and June retail sales data all due at 8:30 a.m. May business inventories data is due later in the session at 10 a.m.

Chemicals maker Albemarle Corp (ALB) said it would buy rival Rockwood Holdings Inc (ROC) for $6.2 billion to bulk up its lucrative specialty chemical offerings.

In other M&A news, Reynolds American (RAI) said it would acquire Lorillard in a deal valued at about $27.4 billion. Lorillard shares were down 3.7 percent to $64.73 in premarket trade.

European stocks fell as declining investor morale hit Germany's benchmark DAX equity index and lingering worries over Portuguese bank BES weakened the Lisbon stock market.

Asian shares rose after Citigroup's (C) earnings and a fresh round of merger and acquisition activity in the U.S. healthcare sector lifted global stock prices.