David Einhorn's Greenlight Capital hedge fund reported new holdings in several big retailers as of the end of December.
The fund reported new stakes in nearly two dozen companies, including a 6.2 million share stake in department store operator J.C. Penney, 125,000 shares in Nordstrom and 132,000 shares in Kohls. Greenlight also disclosed a new 103,000 share stake in Signet Jewelers, 451,000 shares in Under Armour, and 103,000 shares in Best Buy.
In the same period, Greenlight dissolved stakes in Monsanto, Rite Aid, Hewlett Packard and Kroger.
The fund also disclosed a 2.7 million share stake in Twitter. CNBC previously reported in January that Greenlight Capital had bought a stake in the social media platform.
Investment managers are required to report major stakes each quarter, though with a delay that means they may have changed their holdings since the end of the reporting period.
But if Greenlight didn't change anything, some of its new bets are already paying off. Twitter shares are up 40 percent year to date, according to FactSet. Shares of J.C. Penney are up 16.8 percent, and Under Armour up 23 percent.
Greenlight got crushed in January, dropping 6.6 percent during the best month for the S&P 500 since early 2016. That came after the fund returned 1.6 percent for 2017 versus the market's 19 percent gain. The fund's fortunes may have reversed this month after the market's sharp sell-off.
Einhorn has talked about the fund's struggle with bearish bets on stocks that went the opposite direction, including Amazon, Netflix and Tesla. The fund also lost its bid last year to gain seats on the board of General Motors in an activist push.