Stock indexes stepped higher in the first hour and a half of trade Thursday and then reversed to a third straight loss. The Nasdaq’s dent was 0.5%, while the S&P 500 took a 0.6% hit. The IBD 50 was flat. Volume rose modestly on the NYSE and eased on the Nasdaq. The action slapped the S&P 500 with a distribution day, lifting its net change to two adds since the uptrend resumed June 16. The Nasdaq’s net change is zero in the same period.