US STOCKS-S&P 500, Nasdaq dip on Yellen's comments; Apple up late
* Yellen, Fed policymakers: Some U.S. stock valuations 'stretched'
* JPMorgan, Goldman shares rally after earnings
* Fund managers see stocks overvalued, buying anyway -BofA
* Dow up 0.03 pct; S&P 500 down 0.2 pct; Nasdaq off 0.5 pct (Updates with Apple-IBM deal)
By Angela Moon
NEW YORK, July 15 (Reuters) - U.S. stocks pulled back on Tuesday after Federal Reserve Chair Janet Yellen and her fellow Fed policymakers raised concerns about "substantially stretched valuations" in some sectors.
But the major U.S. stock indexes closed well above session lows with the Dow Jones industrial average erasing all of its earlier losses.
In the monetary policy report accompanying her congressional testimony, Yellen said that "equity valuations of smaller firms as well as social media and biotechnology firms appear to be stretched."