Stocks have bottomed, and it's time to go long, Dennis Gartman of The Gartman Letter said Wednesday.
"I own a little bit," he said. "I think it's the right thing to do."
The Dow Jones Industrial Average rallied 149.83 points, or 1.02 percent, to end at 14,910.14. The S&P 500 climbed 15.23 points, or 0.96 percent, to close at 1,603.26. And the Nasdaq bounced 28.34 points, or 0.85 percent, to finish at 3,376.22.
(Read More: Stocks Close Up 1%, Dow Soars 150; AAPL Ends Below $400)
On CNBC's "Fast Money," Gartman said that he was now reversing his previously "agnostic" view on the stock market.
"Yesterday's lows better hold, and I think that they probably shall," he said. "I was really quite impressed by the ability of the stock market to accept a uniquely bad GDP report, second revision of a report that was due six months ago, and it took it very well."
(Read More: Futures Hold Gains After GDP Report)
Gartman also revealed a bit more detail about his positioning.
"Heretofore, I've been long of stock and short of gold, and I've been long of the stock market and perhaps every once in a while trading crude oil against it, but this is the first time I've actually stepped up to own stock indices outright long," he said.