But Blick newspaper reported last week that the backing has now run dry.
Gantenbein confirmed: "The formula one system is sick."
Neue Zurcher Zeitung newspaper claims that Gantenbein and Leimer's management made serious proposals regarding 2014 with three F1 teams, including the Swiss team Sauber.
"I would be willing to pay a low double-digit million amount, if he (Leimer) is involved," said Gantenbein.
"It is a paradox that success has led Leimer to a dead end."
Leimer's manager Stefan Meier, however, denies that luck has run out completely.
"If it does not work out for this season, we will plan for 2015," he insisted.