Rocket Lab just told Wall Street its big bet to challenge SpaceX is slipping another year — and investors punished the stock hard.

In an SEC filing released October 14, Rocket Lab said the debut of its medium-lift Neutron rocket — previously targeted for the fourth quarter of 2026 — is "now expected to occur in 2027." Shares plunged as much as 10% in the session that followed and closed down 6.6%, after sliding roughly 7% in after-hours trading the moment the news first broke.

The numbers behind the nosedive

The damage compounds a rough year for the stock. Rocket Lab (Nasdaq: RKLB) traded around $53 a share following the announcement, putting it down roughly 30% year-to-date and about 65% below its 52-week high of $150.23, set in May 2026, according to trading data reviewed by Yahoo Finance. The stock has swung by more than 5% on 85 separate days over the past year — a volatility streak that has made it a favorite, and a nightmare, for retail traders chasing the space race.

Rocket Lab's own release was sparse on specifics, pointing investors to a presentation on its investor relations site for details. But outside reporting has tied the slip to manufacturing problems with Neutron's first-stage propellant tank, part of the carbon-composite structure central to the rocket's reusable design — the same tank that ruptured during a pressure test back in January.

NEUTRON WAS SUPPOSED TO BE THE ANSWER TO FALCON 9. NOW IT'S BECOME A YEAR-OVER-YEAR EXCUSE.

Neutron is Rocket Lab's shot at the lucrative medium-lift launch market currently dominated by SpaceX's Falcon 9 — a leap from the small-satellite Electron rockets that built the company's reputation. Executives have repeatedly flagged the ambitious timeline as fragile, warning as recently as August that the "window" for an end-of-2026 debut was narrowing even as they held the line on guidance.

Thursday's filing finally made the slip official, and traders who had hoped for a Q4 launch catalyst instead got confirmation that the payoff — and the launch revenue, government contract milestones and investor goodwill that come with it — is pushed out another year.

Not everyone on Wall Street is bailing. Several analysts have kept bullish ratings through earlier Neutron setbacks this year, arguing that Rocket Lab's Electron launch business and satellite-component manufacturing continue to grow even while Neutron eats cash. Still, the repeated delays — this is at least the third public schedule shift since Neutron was unveiled — have worn on sentiment, and the stock's valuation remains tightly bolted to a rocket that still hasn't flown.

Rocket Lab has not given a specific 2027 launch date, leaving shareholders to wait for the next earnings call — expected in the coming weeks — for any firmer target, or further bad news about the tank that keeps grounding the company's biggest bet.