Shares of Dow, the largest U.S. chemical company, fell 6 percent as investor concern mounted that Dow would not be able to fund the $15.3 billion acquisition of Rohm & Haas.

Dow had planned to use the proceeds from the joint venture with Kuwait's state-run Petrochemical Industries Co to repay a large part of the $13 billion of debt from the acquisition.

The Midland, Michigan, chemicals maker agreed to buy Rohm & Haas in July to broaden its specialty product offerings, in a deal that carried a termination fee of $750 million for Dow.

Dow did not return calls asking whether the joint venture's collapse would affect its plan to buy Rohm & Haas.

Rohm & Haas said in a statement on Sunday that the completion of Dow's joint venture was not a condition for the closing of its takeover. It said it was working to complete the deal early next year.

But it would be difficult for Dow -- already facing one of the worst slumps ever in chemical demand -- to access tight credit markets and finance the deal in the absence of the money it had expected from the joint venture.

Shares of Rohm & Haas fell to $52.38 in Monday pre-market trade while shares of Dow Chemical slid to $17.78.

If the acquisition does fall through, it would join a long list of deals withdrawn in 2008 amid a lack of available credit and plunging stock markets.

More deals were canceled this year than ever before, with the total value of withdrawn deals valued at nearly $800 billion.

Dow and other chemical companies are struggling because of recessions in most developed countries and a sharp slowdown in emerging economies. The company earlier this month said it would close 20 facilities, divest several businesses and cut 5,000 jobs to cope with the slump.

(Reporting by Jui Chakravorty Das; Editing by Steve Orlofsky)