The Ibrox side said on Friday night that they were investigating reports that messages posted on a fans' forum were linked to Ahmad's official Rangers email account.
The comments reportedly accused manager Ally McCoist and former boss Walter Smith - now on the board - of attempting to take over the club without putting any money in.
Ahmad was part of the Charles Green consortium which purchased the business and assets of Rangers last summer.
Green resigned last week following claims by former owner Craig Whyte that he was involved in the acquisition.
The Rangers board have commissioned an independent investigation into the claims.
Rangers have confirmed Ahmad's departure but said there would be no further comment.
- Sports & Recreation