Harpoon Hit With Investor Lawsuit for $680 Million Sale to Merck

An investor sued Harpoon Therapeutics Inc. on Thursday over fears that its planned $680 million sale to Merck & Co. may be aimed at handing a windfall to insiders who were given cheap equity before the transaction.

The lawsuit seeks internal files to investigate concerns that a board with ties to New Leaf Venture Partners pushed for an underpriced sale so the investment firm could turn a quick 350% profit on securities it got at a huge discount. The complaint in Delaware’s Chancery Court was filed a day before Harpoon’s stockholders are set to vote on the deal Friday.

The ...