"They have got the money but it's a question of whether they are going to spend it," the Independent newspaper quotes him as having told F1 business journalist Christian Sylt.
It is believed the FIA recently delayed a decision over Haas' 2015 application pending F1s chief executive Ecclestone's 'ok'.
Money seems to have been the 83-year-old Briton's main concern.
"A billion would last a new team owner four years," Ecclestone said. "I've spoken to Haas but I don't know what they are going to do. It's America, so I don't know."
He also didn't rule out the possibility more teams could soon be following Haas into F1.
"Every year we or the FIA have approaches from new teams," he said.