Repros Therapeutics Inc (NASDAQ:RPRX), Aquinox Pharmaceuticals Inc (NASDAQ:AQXP) and Signet Jewelers Ltd. (NYSE:SIG) are today’s top-gaining billionaire stock picks midday. The losers are Williams-Sonoma, Inc. (NYSE:WSM), Bio-Reference Laboratories Inc (NASDAQ:BRLI) and Violin Memory Inc (NYSE:VMEM).

Williams-Sonoma

Repros Therapeutics Soars on Data Reports

Repros Therapeutics Inc (NASDAQ:RPRX) reached the middle of the day up +19.11% this Thursday after reporting positive top line data on one of its products. Farallon Capital initiated a position in the biopharmaceutical company during the first quarter of 2013 and holds 700,000 RPRX shares as of the second quarter of this year. Repros has gained +19.13% YTD.

The share price of Aquinox Pharmaceuticals Inc (NASDAQ:AQXP) climbed +9.05% today – largely the result of a jump in trading volumes. On the 12th of August, the Farallon Capital pick released earnings data, missing the mark on per-share earnings by $0.24. Despite today’s jump, Aquinox is down -37.29% year-to-date.

Up +6.69% midday, Signet Jewelers Ltd. (NYSE:SIG) takes the last spot on today’s list of gainers. The explanation? Reports of a 39% revenue increase in Q2 thanks to its Zale acquisition earlier this year. Billionaire investor Richard Chilton increased his SIG allocation to 400,000 assets in the second quarter of the year, and Farallon Capital initiated a position of nearly 700,000 shares.

Williams-Sonoma Dives After Yesterday’s High

Williams-Sonoma, Inc. (NYSE:WSM) dipped -10.78% early in the day today, just one day after hitting a 52-week high. The company met expectations for quarterly results but issued a weak guidance for Q3. Steve Mandel initiated a position in the home products retailer during the second quarter of this year.

Bio-Reference Laboratories Inc (NASDAQ:BRLI) fell -8.54% midday following its quarterly results report yesterday. Still up +15.98% for the year, the clinical testing lab has been in the Tiger Global portfolio since the second quarter of 2013.

Violin Memory Inc (NYSE:VMEM) hit midday with a loss of -8% on the day. The company beat analysts’ EPS estimates with its quarterly results release yesterday but suffered as both Bank of America and Pacific Crest reiterated underperform ratings on the stock. The George Soros pick is down -44.87% over the past year.