Bermuda-based Fletcher International Ltd. has bought $5 million worth of stock in US company Syntroleum Corp., according to a filing with the US Securities and Exchange Commission (SEC).

Syntroleum filed paperwork last Wednesday indicating Fletcher International was exercising its right to purchase almost 1.9 million shares of the Tulsa-based firm's common stock.

Fletcher International will pay $2.6423 per share. In connection with the purchase, Syntroleum is obligated to issue a warrant allowing Fletcher International to buy more than 2.3 million shares of stock by December 30, 2015.