The Dow industrials and the S&P 500 added to gains while the Nasdaq turned positive on Thursday after a reading of business conditions in the U.S. Mid-Atlantic region came in much better than expected, suggesting a more stable manufacturing sector.

The Dow Jones industrial average <.DJI> gained 55.17 points, or 0.65 percent, to 8,552.35. The Standard & Poor's 500 Index <.SPX> rose 7.45 points, or 0.82 percent, to 918.16. The Nasdaq Composite Index <.IXIC> added 3.20 points, or 0.18 percent, to 1,811.26.

(Editing by Padraic Cassidy)