According to AS newspaper, Martin apparently bought 2011 and 2012 single seaters as well as other assets.
But Reuters reports that another HRT buyer was Pirelli.
"The other 2011 (HRT) car has gone to Pirelli," Martin is quoted as saying.
Pirelli has not confirmed the report.
Currently, Pirelli's F1 test car is a 2010 Renault. Previously, the Italian marque used a 2009 Toyota.
Meanwhile, McLaren boss Martin Whitmarsh fears other teams are in danger of following HRT out of formula one, claiming that "of the 11 teams, seven of them are in survival strategy".
"It's tough," Whitmarsh, referring to the economic situation, is quoted by the BBC.
"We have taken some measures but I think it's going to be tough for some of the teams to have a viable business model for a few years; there's no doubt about that."