Port Vale chairman Paul Wildes has quit just six months after becoming co-owner of the club and three weeks after they won promotion to League One.
Wildes led Vale out of administration when he and his Alchemy Investment Group bought the club in November 2012.
But the 36-year-old has sold his 50% share to his business partner, Vale's chief executive Norman Smurthwaite.
"From many conversations with Norman, it's clear we have conflicting ideas on how to take Vale forward," said Wildes.
"This sometimes happens in business and, because of this, I have decided to step down.
Paul Wildes the businessman
- Sheffield-born Paul Wildes, 36, runs a variety of businesses, from hotels to hairdressers
- A former finance director for the Caudwell Group, which owned brands such as Phones 4u, Wildes owns some of the franchise for the hotel chain Holiday Inn
- He set up his own company in 2007, Mansion Group, which he sold three years later, before establishing a new holding company, the Wildes Group
- The boyhood Sheffield Wednesday fan also attempted a takeover at Darlington last year
"I know there will be a level of disappointment among sections of the supporters, but this is not a decision I have taken lightly.
"This has been an incredibly difficult decision for me. My main regret is that I am leaving the job half-finished. But Vale are now in a far healthier position than when we took over and I hope the club continue to prosper under Norman's guidance."
Smurthwaite, who will now become Vale chairman and sole owner, commented: "I would like to reassure fans this is business as usual.
"There is no-one more disappointed than me that Paul has decided to leave, but this is business and we have to move on.
"Paul has done an excellent job as chairman - but now is the time to look to the future.
"It's also important to understand that, financially, this will not affect the club going forward. I have already invested heavily in Port Vale and will continue to do so. The financial security of the club is not in jeopardy."
Operations director Mike Aspinall and finance director Robin Anderson have also left the club.