Amazon was granted warrants to purchase up to $340 million worth of Generac stock, sending shares of the backup power provider soaring more than 40% in extended trading on Wednesday.

As part of the agreement, Generac said in a securities filing that it issued warrants to Amazon to acquire up to 1.69 million shares in the company at $200.93 a piece for a total investment that could be worth as much as $8 billion.

Generac will supply Amazon with backup power generators for its data centers, with initial deliveries expected to total $2.4 billion in 2027 and 2028, the filing states.

About 308,000…