A hedge fund based in the Isle of Man has taken a 5% share in Rangers.

Details released this afternoon by the London Stock Exchange showed that Laxey Partners now holds 3,250,000 shares and has 4.99% voting rights.

It was known that around two million Rangers shares had changed hands on Monday, and today's details were published because Laxey now has a stake above the 3% threshold which requires disclosure.

The acquisition was made in the name of Credit Suisse Client Nominees UK. No further details were made public.

It remains unclear who sold the shares, although former chairman Charles Green is prevented from transferring any of his stock until December.

Rangers announced in June that Green had agreed to transfer over half a million shares to Laxey. The deal was struck last October but, under the terms of a lock-in agreement, the transfer of Green's 714,285 shares to the Isle of Man-based investment firm cannot take place before December 7.

It is expected that Laxey has acted because it believes the current share price, of 41.5p, undervalues the club.

As a hedge fund, it would hope to make a profit if the price rose naturally during a takeover, or if its 5% shareholding became particularly valuable to one or both sides of an ownership battle.

Laxey Partners has a history of buying small stakes in firms and then lobbying aggressively for changes that will make shareholders money.

Fans have expressed concerns about the impact the fund, under manager Colin Kingsnorth, could have at the club following the shares sale in October 2012, with a member of the Rangers Supporters Trust claiming Laxey Partners' "pattern of behaviour in other companies is worrying".

The confirmed trading follows a volatile week for the club with the departure of chairman Walter Smith, the return of former chief executive Charles Green, sparking fans' protests, and a bid to overhaul board membership.

Tycoon Jim McColl has ­requisitioned an EGM to seek the support of the majority of shareholders to have former club director Paul Murray and finance expert Frank Blin parachuted into Ibrox.

He hopes to oust chief executive Craig Mather, finance director Brian Stockbridge and non-executive director Bryan Smart from the board.

Meanwhile, Rangers have vowed to "robustly defend" any legal action taken against the club by former commercial director Imran Ahmad.

Reports today suggest he is set to launch a £3.4million legal action against the Light Blues for bonuses he says he is owed.

Ahmad left the Glasgow giants in April - 24 hours after Rangers confirmed they were investigating reports that messages posted on a fans' forum were linked to his official club email account.

Ahmad was part of the Charles Green consortium which purchased the business and assets of Rangers last summer.

Green resigned as chief executive in April but has since returned to Ibrox as a club consultant.

Responding to today's reports, Brian Stockbridge said: "We are aware of this but it is without legal merit and any action will be robustly defended on behalf of the club and its fans."

Ahmad was quoted saying: "It's true the club does owe me money.

"Charles Green has agreed to tell the truth if it goes to court, ie I am due a five per cent bonus on all the commercial deals I negotiated on behalf of club.

"I am hardly going to turn my back on a bonus which is due to me when I've directly negotiated £67million worth of contracts which benefit the club over the next five to 10 years.

"Neither I nor Charles have ever wanted this to go to court as we are substantial shareholders and in fact Charles had already brokered a deal with the club for a fraction of the full liability but the club has not signed up to it.

"I had also offered to reinvest all my bonus proceeds plus an additional extra £500,000 of my own money back into the club.

"At least this shows how much I've contributed to the club and the fact that I am prepared to put more cash into the club."