He told Sky Blues Player: "That money that we could spend exercising the option (to buy 50%) would be better served for the football club in strengthening the team and other areas.
"As and when the time is right, we've got an option until 2015, it's certainly something we want to do but only when it's commercially viable."
He continued: "In an ideal world, you buy it when you're in the Premier League and there's 25,000-28,000 people here because then the commercial revenues that the other businesses within the arena generate make it worthwhile.
"At the moment, the position we're in - mid-table with average gates of 16,000-17,000 - mean it is not commercially viable at the moment. So we are in a chicken and egg situation for want of a better phrase."