What a day.

The Dow whipsawed from down 170 points to closing up 10 points, thanks to a surge that started around 2 p.m. and really shot higher at 3 p.m. What do market watchers make of it?

"I think the surge higher was triggered by dramatically better than expected (depends on how you view it) change in Consumer Credit that was released at 3 p.m," wrote Howard Ward, portfolio manager of theGAMCO Growth Fund, in an email to MarketBeat.

"The consumer is almost back to borrowing which means he is feeling better and will spend more."

Strategist Robert Pavlik of Banyan Partners said buying began to pick up after the S&P 500 hit its intraday low around 1044 around 2 p.m. That level represented a 9% pullback from its recent high set in late January, close to the 10% threshold that traditionally defines a market correction.

"Once we got close to that 10% level, people started jumping the gun to get back in early," in anticipation of a short-term market bottom, said Mr. Pavlik. "From there, it just built on itself as we went into the close."

While the S&P finished up 0.3% and the Dow up 0.1%, the Nasdaq 100 performed much better, adding 0.8% on the day.

"To me the most telling thing about the day was that technology stocks did not break down with the rest of the market," wrote Nicholas Colas, chief market strategist at BNY Convergex Group, in an email.

"This has been one of the worst performing groups of 2010 as investors de-risked portfolios. So when they didnt follow through on the sell off today through midday, I think that caught peoples attention and was perhaps somewhat of a catalyst for a short covering rally into the close."