The Big Reason ImmunoGen, Inc. Shed 24% of Its Value in October

Shares of ImmunoGen (NASDAQ: IMGN), a small-cap biotech company focused on the development of antibody-drug conjugates for the treatment of cancer, plunged 24% in October, according to data from S&P Global Market Intelligence. The culprit for ImmunoGen's miserable month looks to be none other than a common stock offering.

On Oct. 11, ImmunoGen announced that it generated $108.4 million in gross proceeds by selling 16,675,000 shares of its common stock, which included a 2,175,000 share option that was fully exercised by the underwriters of the offering. The price of the stock offering, $6.50 a share, was 15% below where the company began the month.

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Source: Fool.com