Fimbra said it appeared that the firm did not have adequate resources to meet its liabilities.
Claremont Savile devised a way for parents to release equity in their homes and use the money to pay school fees.
The scheme, launched in 1983 in conjunction with National Westminster Bank, was endorsed by Isis, the Independent Schools Information Service.
NatWest stopped dealing with Claremont Savile in May 1992.
Isis severed its relationship about a month ago. An Isis spokesman said: "It was as a result of increasing concern over adequate controls over branches around the country. It had established franchises in 1992 and there seems to have been a loss of central control.''
The firm advertised in the Isis handbook and it is one of the creditors. Isis said that once customers had been introduced to a lender by Claremont Savile they would then have a relationship with the lender and Claremont Savile would no longer be involved.