The Trump administration issued a stop-work order, over national security concerns, on a nearly completed offshore wind project for Massachusetts and Rhode Island.

Denmark’s Orsted lost almost a fifth of its market value at one point as investors sold the offshore wind champion’s shares. They were reacting to orders by President Donald Trump to cease developing an almost-finished project in the northeast US.

An order to stop work on the Revolution Wind project off Rhode Island further rattled the beleaguered Danish company.