After Merrimack Pharmaceuticals Inc. (NASDAQ:MACK)’s stock plummeted by over 10% yesterday, some insiders were clever and took advantage of the price changes regarding the company’s stock, allowing them to purchase large amounts of stock. The talk is of company directors Gary Crocker and Michael Porter.

With Merrimack’s stock at a low price of $6.84 per share, Crocker acquired 36,000 shares, indirectly, through his spouse. In spite of the large bulk of stock, this isn’t Crocker’s first purchase this year, as he reported several smaller stock acquisitions in May of this year. Michael Porter bought 32,390 shares of the biopharmaceutical firm, directly, at the same price as Crocker, bringing his total holdings up to 568,255 company shares.

Insider trading overall has been quite active at Merrimack over the past few months, with many reported stock acquisitions, as well as large sales. Most recently, Senior Vice President and CSO Ulrik Nielsen sold off 105,000 of his company shares, at $8.01 per share, thereby substantially diminishing his shareholder position in the firm.