Just six months after defense tech Anduril raised a massive $1.5 billion round that valued the company at $14 billion, it’s in talks to raise another $2.5 billion, at a valuation of up to $28 billion, sources told CNBC.

The deal would, not surprisingly, be led by Founders Fund, which is reportedly writing a $1 billion check that represents its largest check ever. While Anduril founder Palmer Luckey is the face of the company, it names five men as co-founders, among them Founders Fund partner Trae Stephens. Founders Fund has been an investor in Anduril from the start, leading its seed round in 2017. It also co-led Anduril’s 2024 financing.

That previous round was to help pay for Anduril’s billion-dollar weapons megafactory it is building in Ohio. Sources also told CNBC that the company’s 2024 revenue doubled to $1 billion. Anduril declined further comment.