General Fusion Inc., a Canadian startup backed by Jeff Bezos, is making a plea to investors after raising more than $300 million to develop a system that would harness the power of the stars.

“We are ready to execute our plan but are caught in an economic and geopolitical environment that is forcing us to wait,” Chief Executive Officer Greg Twinney wrote in a open letter Monday. “All we need now is the capital to finish the job.”

General Fusion is actively seeking strategic options with investors, buyers and governments, according to the letter.

The company has fired at least a quarter of its staff and is scaling back operations due to lack of capital, according to Grace Peach, a spokeswoman. General Fusion is also seeking $125 million in additional funding to complete its fusion demonstration system.

The turbulent geopolitical and economic environment, including tensions in US-Canada trade relations, has caused financial uncertainty for investors and governments, Peach said by email. That’s prompting potential backers to be more cautious and move slowly.

Interest in fusion has climbed since 2022, when a US government laboratory in California managed to trigger a reaction that generated more energy than was needed to set it off. But the engineering and technological challenges are steep and progress has been slow. General Fusion achieved a significant milestone in April, but the company still needs to raise funds.

Bezos has participated in multiple funding rounds for the company, which last month hired as a strategic adviser the former CEO of the Amazon.com Inc. founder’s rocket company Blue Origin LLC.

“Today’s funding landscape is more challenging than ever as investors and governments navigate a rapidly shifting and uncertain political and market climate,” Twinney said.