Stratolaunch Systems — the aerospace company created by the late Microsoft co-founder Paul Allen — is changing ownership. The company announced today that it is no longer owned by its original holding company, Vulcan Inc., and has been sold to a now undisclosed owner.

The news comes four months after reports started surfacing that Stratolaunch was on the brink of closing up shop, following the death of Allen in October of 2018. CNBC then reported in June that the company was up for sale, valued at $400 million. At the time, Virgin Group founder Richard Branson was supposedly interested, as Stratolaunch uses similar launch technology to the billionaire’s space companies, Virgin Galactic and Virgin Orbit. However, Branson reportedly pitched buying Stratolaunch for $1, according to CNBC.

Stratolaunch, based in Seattle and Mojave, designed and built a massive carrier aircraft, made to hoist rockets into the air and launch them to orbit. With a wingspan of 385 feet, the dual-fuselage plane is considered the biggest in the world. Stratolaunch flew the vehicle for the first time in April on its one and only test flight. The company had an agreement to fly Northrop Grumman’s Pegasus XL rockets from the plane, but those flights never took place.

In 2018, Stratolaunch announced that it would design a fleet of rockets for the plane to carry, including a spaceplane. But a few months after the death of Allen, the company announced that it was scaling back operations and would no longer develop new rocket systems. “We are streamlining operations, focusing on the aircraft and our ability to support a demonstration launch of the Northrop Grumman Pegasus XL air-launch vehicle,” the company said in a statement to GeekWire at the time. Stratolaunch employs only 21 people currently, a sharp decrease from the 77 workers it had in December, according to Reuters.