A new national study indicated that a majority of U.S. businesses – especially small businesses – want to expand their companies, but are being held back by a lack of capital and tightened credit.

The Pepperdine University Private Markets Capital Project showed that just 40% of privately held companies have the on-hand resources to expand. The study covered some 560 businesses and 1,400 financial firms, including banks, venture capitalists, private equity firms and even alternative lenders.

According to Pepperdine business professor John Paglia, who headed the study, businesses are frustrated in their efforts to expand and hire because they cannot get business loans. "It’s inhibiting growth opportunities," said Paglia.

The study, Paglia also said, showed a high rate of optimism among business owners, despite capital and credit restraints, raising concerns that some owners might make highly risky moves.

In addition, he said, the study indicates that small business – seen as key to U.S. economic recovery – could be in worse shape than believed.

Regarding the credit crunch, the survey showed that lenders and investors are rejecting 90% of loan and investment requests that would be secured by real estate, and they refuse 73% of requests for loans or investments based on cash flow.

More than half of business owners surveyed said they had to turn to friends and family for money. Only 33% said they had obtained bank loans, and 10% sought out alternative lenders.