According to SEC Form 4 filings between October 25 to December 4, 2017, insiders at Celgene Corp. (NASDAQ:CELG), one of the top five constituents of the iShares Nasdaq Biotechnology ETF (NASDAQ:IBB), bought a total of 84,870 shares at prices between $31.21 per share and $98.17 per share in 4 transactions and sold 1,088 shares at $98.17 per share in one transaction, as shares of Celgene plunged about 35% in less than a month from its all-time high at $147.17 per share. Insiders might have thought that Wall Street was overreacting to the company's negative news announcements.
Sanofi S.A. (NYSE:SNY) said in a SEC Form 4 filing on September 25, 2017 that it purchased 166,413 common shares of Regeneron Pharmaceuticals Inc. (NASDAQ:REGN) through its subsidiary Sanofi-Aventis Amerique du Nord from September 23 through September 24, 2017, at prices ranging from $467.78 per share to $488.82 per share. Sanofi now owns about 23.81 million outstanding shares, or a 20.35% stake in Regeneron. Sanofi might have thought that Regeneron shares were undervalued after it plunged over 20% from its June high of $543.55 per share. In January this year, Sanofi bought 87,298 common shares of Regeneron at prices ranging from $361.76 per share to $379.80 per share, after the stock sold-off almost 25%.
