Saints fans are calling for transparency over a mystery financial document that has been lodged by the club at Companies House.

The document, on public view, is headed ‘particulars of a mortgage or charge’ and appears to suggest that the football club have agreed a substantial loan with a company from the tax haven of the British Virgin Islands called Vibrac Corporation.

Vibrac have been involved in football before, loaning Everton £14m last year.

In effect the Everton loan was an advance on future income, and secured against either cash generated from another campaign in the Premier League or, in a worst case scenario, the bumper parachute payments offered in the event of relegation.

The Saints documents also mention parachute payments and amounts earned if in the Premier League for 2013/14.

There is no detail of any amounts borrowed in the document, nor any mention of repayments or fees.

Saints, under the leadership of executive chairman Nicola Cortese, have been able to proudly boast of their lack of debt since the takeover by the late Markus Liebherr and, though this may just prove to be nothing out of the ordinary, it has nevertheless got fans worried.

A spokesman for the Southampton Independent Supporters Association said: “We would very much like to see some transparency on this issue.

“Hopefully this is not anything significant but the fans would certainly like it to be explained as we have been told we are debt free.

“It would be the sort of question that would be raised at a fan’s forum but we have not had one for several years, even with the likes of Portsmouth and Bournemouth holding them despite everything that has been going on at those clubs.”

Although the document was made public in the week that work stopped at the training ground due to a “specific aspect” of the development and programme sellers were laid off, it is not believed that the matters are linked.

Football finance experts who assessed the document for the Daily Echo confirmed that it may just be a loan facility, or effectively an advance of some of next season’s cash to allow significant squad strengthening in January.

Saints spent more than £25m this summer in preparation for their return to the Premier League.

The club did not respond to the Daily Echo’s request for a comment.