Stake also sponsor English Premier League football side Everton.
No financial details were given, although a team statement described the deal as record-breaking.
The outfit run by Swiss-based Sauber will be officially known as Alfa Romeo F1 Team Stake this season, with Alfa due to depart at the end of the year and the team becoming Audi from 2026.
"Formula One has seen a huge increase in interest over the last few years and the arrival of brands such as Stake are representative of the massive exposure our sport can offer," said Sauber managing director Alessandro Alunni Bravi.
Oil and gas company PKN Orlen have backed Polish driver Robert Kubica, Alfa's reserve for the past three years, and the departure looks likely to signal the end of his Formula One career.
The 38-year-old race winner last competed in Formula One as a replacement for now-retired Kimi Raikkonen at two grands prix in 2021 after the Finn tested positive for COVID-19.
Red Bull-owned AlphaTauri said Orlen's branding would appear on the car, including the rear wing, and driver apparel.
