Ford Motor Co. (F) plans to raise the amount of a borrowing plan to roughly $22 billion to $23 billion from an original $18 billion, as it increases the size of a revolving credit line and a convertible note sale.

In a filing with the Securities and Exchange Commission, Ford said on Wednesday it is increasing the amount of a secured revolving credit facility to roughly between $10.5 billion and $11.5 billion from $8 billion.

Ford last week said it plans to borrow $18 billion by pledging assets as collateral for loans in a plan that included about $8 billion in secured revolving credit.

The second-largest U.S. automaker cited "overwhelming support by lenders" for the increase in its credit line.

Ford on Wednesday also increased the size of a convertible note sale to $4.5 billion from $3 billion, according to market sources familiar with the sale.

That offering is expected to be priced later on Wednesday, the sources said.

The borrowing originally included $3 billion in unsecured notes that can be converted into Ford common stock.

A secured loan of about $7 billion remains unchanged, Ford said.

The borrowing plan, which prompted ratings cuts by all three credit rating agencies, is expected to finance Ford's efforts to rescue its North American operation, which has lost $12.39 billion before taxes and including special items since January 2005.

The borrowing will be backed by assets including U.S. auto plants, stock of subsidiaries including Ford Motor Credit Co. and Volvo, and up to $4 billion in domestic cash.