Recently, various healthcare executives have taken part in insider buying activity for the stocks of Merrimack Pharmaceuticals Inc (NASDAQ:MACK), Opko Health Inc. (NYSE:OPK), NewLink Genetics Corp (NASDAQ:NLNK), and GTx Inc (NASDAQ:GTXI)

Merrimack Pharmaceuticals Inc

Director Michael Porter bought $8,284 shares worth $$97,668 at an average price of $11.79, as reported in the SEC filing on May 15. Following the insider-buying transaction, his stake in Merrimack Pharmaceuticals has now grown to $661,448.00 shares with a value of $8,221,799.

Opko Health Inc.

Opko Health has been backed by positive insider activity as the company’s CEO & Chairman, Phillip Frost, acquired a total of $6,000 shares in multiple transactions dated May 13, taking his total stake to $176,876,336 shares. The stock purchase was worth $93,315 at an average price of $15.55 per share.

NewLink Genetics Corp

Chief Financial Officer and Executive Vice President John Henneman yesterday purchased $3,000 shares, valued at $111,900. After completion of the transaction, Henneman owns 50,489 NewLink shares, worth $1,952,410.

GTx, Inc.

The Executive Chairman of GTx, Wills Robert James, acquired 46,140 shares (worth $44,247) at a price of $0.96 in two transactions dated May 13 and May 14. The executive now has a total stake of 100,000 GTx shares worth $100,000.

According to, which measures corporate insiders’ success based on their transactions, Wills Robert James has an average return of 7.9% and a 66.7% success rate. James is ranked #12459 out of 35774 corporate insiders.