Stocks were mostly lower in volatile trading Tuesday, failing to maintain early gains one day after suffering steep losses. The Dow Jones industrial average fell 100.69, or 0.4 percent, to 25,286.49. The broader Standard & Poor's 500 index fell 4.04, or 0.15 percent, to 2,722.18. The technology-heavy Nasdaq composite index was virtually unchanged at 7,200.88, after climbing as much as 1.6 percent earlier in the session.