International Tower Hill Mines Ltd (NYSEMKT:THM), Freddie Mac / Federal Home Loan Mortgage Corp (OTCBB:FMCC) and Oncothyreon Inc (NASDAQ:ONTY) are the top gainers on the market midday today. Concert Pharmaceuticals Inc (NASDAQ:CNCE), NanoString Technologies Inc (NASDAQ:NSTG) and Arrowhead Research Corp (NASDAQ:ARWR) are the day’s biggest losers midday.

George Soros

Soros’ pick Oncothyreon Jumps

Its price up +7.45% midday today, International Tower Hill Mines Ltd (NYSEMKT:THM) got a strong start to the week. The exploration-stage company has held a place in the investment portfolio of billionaire John Paulson across several quarters and is up +72.93% in 2014.

Freddie Mac / Federal Home Loan Mortgage Corp (OTCBB:FMCC) surged +5%. Bruce Berkowitz has held 61,000 FMCCS shares for two quarters, and the credit provider is up +111.27% over the past year.

Rounding out today’s list of top midday gainers is Oncothyreon Inc (NASDAQ:ONTY), the stock price of which jumped +4.78%.  The biopharmaceutical company has become one to watch in recent weeks, announcing an agreement with Celldex Therapeutics at the end of May and revealing trial data at the start of the month. Its price is up +27.63% over the past month alone – a nice piece of news for billionaire George Soros, who initiated a position in ONTY in Q1.

Soros’ pick Arrowhead Research, and Concert Pharmaceuticals Face Small Setbacks

Concert Pharmaceuticals Inc (NASDAQ:CNCE) – one of Friday’s top midday gainers – went in the other direction today, its price dipping -8.8%. Despite today’s drop, the new Q1 Farallon Capital buy is up +35.49% over the past month.

NanoString Technologies Inc (NASDAQ:NSTG) fell -4.91%, continuing a downward trend that has it posting a 24.6% three-month loss. A first quarter acquisition for George Soros, NanoString develops, manufactures and sells life science tools for translational research and molecular diagnostic products. Last week, news broke that SVP Wayne Burns had unloaded 4,900 NSTG shares.

Arrowhead Research Corp (NASDAQ:ARWR), another Q1 Soros buy, takes the third spot on today’s list of midday losers. The price of the biopharmaceutical company slipped -4.49% – a bit of a price correction after last Friday’s 10.66% surge. Arrowhead has rallied +38.34% in 2014 and +715.76% in the past year.