Thursday was a big down day for the stock market, as major indexes lost around 2.5% to 3%. Bad news from the technology sector was the primary culprit: A sales warning from the maker of some of the most popular smartphones and mobile devices on the planet sent ripples throughout the investing universe. Even with most market participants in a negative mood, some stocks benefited from good news, and Celgene (CELG), Agenus (AGEN 7.30%), and Incyte (INCY 1.38%) were among the top performers. Here's why they did so well.

Celgene makes a deal

Check out the latest Celgene earnings call transcript.

Shares of Celgene soared 21% after the biotech giant got an unexpected acquisition bid from pharmaceutical company Bristol-Myers Squibb. Under the terms of the deal, Bristol will pay $50 in cash along with a share of Bristol stock for every Celgene share that shareholders own, putting a roughly $74 billion price tag on the biotech. From Celgene's perspective, some see the offer as a potential bailout ahead of the expiration of patent protection for its key Revlimid treatment for multiple myeloma, eliminating the risk that its efforts to limit generic competition won't work. Yet opponents point to the fact that Celgene traded well above the current price as recently as last August. Despite Celgene's rise today, the share price still reflects a big discount from what Bristol's offering, suggesting uncertainty that the deal will go forward.

Four-story building with glass front with Celgene logo on it.

Image source: Celgene.

Agenus gets a grant

Check out the latest Agenus earnings call transcript.

Agenus saw its stock climb 11% in the wake of receiving a grant from the Bill & Melinda Gates Foundation. The $1 million award will go toward helping Agenus develop an alternative method for manufacturing the company's QS-21 Stimulon adjuvant, which plays an essential role in numerous vaccines to treat infectious diseases as well as cancer. CEO Garo Armen was pleased with the partnership, and investors are excited that QS-21 is getting recognition that in turn could lead to further collaborations and innovations for the biotech company.

Are better times ahead for Incyte?

Check out the latest Incyte earnings call transcript.

Finally, Incyte shares finished higher by 7%. The company said that it had appointed Christiana Stamoulis as CFO effective Feb. 11, filing a vacant position from the end of 2018. Yet what seemed to motivate shareholders the most was an upgrade from analysts at Guggenheim, who lifted their rating on Incyte from neutral to buy and set an $84 price target. Incyte has gone through tough times over the past year, with poor results in a key clinical trial weighing on the stock. Yet if Guggenheim's right, the worst might be over for Incyte, and shareholders hope the company will continue to recover.