Stocks fell mildly Monday as sellers pounced in the final hour. Some leading stocks got dinged in an otherwise quiet session. After snapping a three-week losing streak last week, the S&P 500 slipped 0.2% after holding a modest gain for much of the session. The benchmark index is less than 1% off its Feb. 25 record high. The Nasdaq wavered to a 0.3% loss. It closed at its session low but held above the 5000 level.