The billionaire owner of Sports Direct and Newcastle United has made a £43m bet on Tesco's future. Following Tesco's admission of a profit error it sent share prices tumbling. Sports Direct said it had entered into a put-option agreement with Goldman Sachs for more than 23 million shares, representing a 0.3% stake in the supermarket business. The move essentially means that Mike Ashley is betting that the Tesco share price will rise. The agreement gives Goldman Sachs the option to sell 23m Tesco shares to Sports Direct at a set price on an agreed future date.