Summit Clubs, the nightclub company owned by former Soho Clubs and Bar chief executive Jeremy Gordeno, has been placed in administration.
Five of its sites were bought from CanDu Entertainment, the company that was placed in administration two weeks ago.
Nightclub company Luminar, which sold its 49-strong enterprise division to a management buy-out that formed Candu, stated: "Under some circumstances, the leases of the leasehold units held by Candu at the time of its disposal in June 2005 could therefore, in due course, revert to companies within the Luminar group.
"The total annual property costs relating to the 35 leasehold units were approximately £4.9m at the time of the disposal in 2005.
"The board is confident that, should any lease reversions occur, Luminar will be able to institute a range of corporate and operational actions to limit substantially any financial impact of such reversions."
Panmure Gordon analyst Douglas Jack said: "One should expect Luminar to consider either sub-letting or trading sites that return to it.
"Alternatively, it may attempt to include sites as part of other property transactions.
"We are not changing our forecasts at this stage, but believe the liability is likely to be £1-3m (3-9% of PBT).
"As a consequence, we are reducing our target price from 525p to 500p."