Stocks making the biggest moves in the premarket: Palantir, Signify Health, Global Blood Therapeutics and more

cnbc.com:

Take a look at some of the biggest movers in the premarket:

Palantir (PLTR) – The data analytics company's stock plunged 15.6% in premarket trading after it reported an unexpected quarterly loss, and lowered its full-year forecast due to the uncertain timing of some government contracts.

Signify Health (SGFY) – CVS Health (CVS) is planning a bid for Signify in an effort to expand in-home health services, according to people familiar with the matter who spoke to The Wall Street Journal. The paper had reported last week that Signify was exploring strategic alternatives including a sale. Its stock surged 16.7% in the premarket.

Global Blood Therapeutics (GBT) – The maker of blood disorder treatments will be bought by Pfizer (PFE) for $5.4 billion, or $68.50 per share in cash. Global Blood shares soared 88% over the past two sessions following reports that a deal was near, and gained another 4.2% in the premarket.

Tyson Foods (TSN) – The beef and poultry producer reported quarterly profit of $1.94 per share, 4 cents a share shy of estimates. Revenue beat forecasts, however, as beef demand remained high. Chicken volume fell 2.1% but Tyson said that business continues to improve. Tyson shares slid 2.5% in premarket trading.

Barrick Gold (GOLD) – The mining company's shares added 3.2% in premarket trading following better-than-expected quarterly results, helped by higher copper output.

Baidu (BIDU) – The China-based search engine company won approval to operate driverless taxi services in two Chinese cities, the first such approvals in the country. Baidu added 1.2% in premarket action.

First Solar (FSLR) – The solar company was upgraded to «buy» at Guggenheim and to «overweight» at J.P. Morgan Securities, with both saying First