FTC sues to block Lockheed Martin acquisition of Aerojet Rocketdyne
The Federal Trade Commission on Tuesday filed suit to block Lockheed Martin 's planned acquisition of Aerojet Rocketdyne , which makes rocket engines and spacecraft propulsion.

The complaint "alleges that if the deal is allowed to proceed, Lockheed will use its control of Aerojet to harm rival defense contractors and further consolidate multiple markets critical to national security and defense," the FTC said in a statement.

Earlier on Tuesday, both Lockheed and Aerojet warned shareholders of the FTC lawsuit. Shares of Aerojet Rocketdyne dropped as much as 15% in trading from its previous close of $45.

The defense giant in December 2020 announced its intention to buy Aerojet at a $4.6 billion equity valuation. The deal was expected to close in the second half of last year, but the FTC's review delayed the transaction until this month.

Lockheed is Aerojet's largest customer, making up about 33% of its sales. United Launch Alliance, or ULA, makes up an additional 10% of Aerojet's sales – a further complement to Lockheed Martin, which owns a 50% stake in ULA as a joint venture with Boeing .

During Lockheed's fourth-quarter earnings conference call on Tuesday, CEO Jim Taiclet said the merger agreement with Aerojet allows for a 30-day review period following the filing of a lawsuit to decide whether to defend or terminate the deal. If the FTC's lawsuit does go to court, the trial is scheduled to begin on June 16.