Rocket Lab USA, Inc. (RKLB) saw its stock plummet 8.19% in after-hours trading following news of a setback in the development of its Neutron rocket. The decline came after the company reported a rupture in the Stage 1 tank during hydrostatic pressure testing.

The incident occurred during qualification testing, a critical phase to validate the rocket's structural integrity. While Rocket Lab confirmed no significant damage to facilities and stated the next Stage 1 tank is already in production, investors reacted negatively to the potential delay in Neutron's launch schedule. The company is reviewing test data to assess the impact and plans to provide an update during its Q4 earnings call in February.

Despite the setback, Rocket Lab emphasized that such testing failures are not uncommon and that the Neutron development campaign continues as scheduled. The market's reaction reflects concerns over potential timeline disruptions for the medium-launch vehicle, which is key to the company's growth strategy.