What happened

Two somewhat under-the-radar biotech companies saw their share prices soar this week after agreeing to be acquired. CinCor Pharma (CINC) is being bought out by deep-pocketed pharmaceutical company AstraZeneca, while Albireo Pharma (ALBO) is set to be owned by France-based peer Ipsen.

Both of these deals are very lucrative, to the point where CinCor's stock rocketed 146% over the course of the week, and Albireo shot 92% skyward, according to data compiled by S&P Global Market Intelligence.

So what

Both deals were announced on Monday, resulting in those share-price blasts. Of the pair, CinCor was the splashier, both in terms of the acquirer and the price. It's also very possible that it'll wrap up quicker: As per CinCor and AstraZeneca's agreement, the latter must initiate a tender offer by Tuesday, Jan. 23.

It's going to be quite the offer. The sale price is $26 per share, a beefy 121% premium to the stock's closing price the previous trading day, which values CinCor at $1.3 billion. And that's without milestone payments, which if fully realized would drive the latter figure up to $1.8 billion. The transaction will be entirely in cash.

As for the Albireo arrangement, Ipsen is acquiring it basically to get its leading investigational drug Bylvay -- a treatment for progressive familial intrahepatic cholestatis (PFIC), a disorder of the liver. That'll cost it $42 per share (putting the total value of the deal at $952 million), with an additional $10 per share contingent upon Bylvay winning Food and Drug Administration approval by the end of 2027. 

Now what

It's safe to say that a great many biotech investors put money into the sector hoping for a giant payday when a big player swoops in for an acquisition. In the case of both CinCor and Albireo, the week's two monster winners in the sector, investor faith was very well placed.