LONDON, United Kingdom - Sports Direct founder Mike Ashley has sold the 4.6 percent stake he bought in Debenhams last month, and taken a complex financial option over a further stake that bets the shares will not fall below a certain level.

Debenhams and Sports Direct, controlled by Newcastle United soccer club owner Ashley, began working together earlier this year, with the department store trialling Sports Direct concessions in its shops.

On Thursday the sports retailer said it had taken a so-called put option over a 6.1 percent stake, to add to an earlier option of 6.6 percent. The move means Sports Direct has a total interest in 12.7 percent of the equity in the department store.

The strike price of the option has not been disclosed.

Ashley has bought a string of stakes in retailers and other companies in recent months, including a similar bet on Tesco shares. Shares in Debenhams have risen by about 11 percent based on the closing prices on the days Ashley bought and sold his latest stake.