Film scheme operator Future Capital Partners may be going into liquidation shortly, its director has announced.
Tim Levy, director of Future Capital Partners, has announced the move, saying it is also possible that the company goes into administration.
In 2016 HM Revenue & Customs won a three-year battle with the company over a film scheme used by celebrities and sports stars to avoid tax.
The Supreme Court dismissed an appeal from Eclipse 35 brought by Future Capital Partners, its creator, and 287 investors, who reportedly include former football managers Sir Alex Ferguson and Sven-Goran Eriksson.
Mr Levy said: "In view of the changed circumstances of Future Capital Partners, it is not appropriate for the existing investor services agreements to continue and, accordingly, all will be terminated with effect from the date of the administration/liquidation of Future Capital Partners. That is expected later this month.
"Therefore, for investors who are signed up to receive services from Future Capital Partners under a services agreement, the February fee instalment was your final payment."
He added that all further services will be provided only via the litigation action group (LAG) and will be priced into funding rounds.
Mr Levy added: "We expect to revert with counsel's opinion in March on the two issues commissioned by the LAG. As no services will be provided to investors who are not members of the LAG, you may wish to join the LAG."
Future Capital Partners also sold and marketed the Elysian Fuels investment scheme, which has caused problems for James Hay but cut the value of the shares in the scheme from £1 each to zero in October 2015.
The provider of self-invested personal pensions is in ongoing discussions with HM Revenue & Customs over a potential solution to the sale of these investments between 2011 and 2015.
James Hay estimates the maximum potential sanction charge for the overall 2011 to 2015 period would be about £20m, assuming all Elysian Fuels shares are deemed valueless at inception.
Michael Cotter, a lawyer at Setfords Solicitors, said: "The fall of Future Capital Partners Ltd is the biggest collapse for the tax/film scheme industry. It will leave thousands of members and investors unsure as to the consequences, in particular leaving those nervous as to the future position of HMRC who may seek to collect millions of lost taxation.
"Investors/members have had concerns as to the performance of FCP and their schemes for many years so this announcement of the closure will come as no surprise.
"It is important to bear in mind that these schemes were not just the preserve of celebrities and the rich and famous, it is also average retail investors who now face losses that have potentially ruinous consequences."