NEW YORK, June 17 (Reuters) - Movie-rental company Blockbuster Inc. (BBI.N: Quote, Profile, Research) and off-price apparel retailer Loehmann's Capital Corp are among nine U.S. retailers that might struggle to fund their operations over the next 12 to 15 months, Moody's Investors Service said on Tuesday.

While liquidity is not a major issue for most retailers, some specialty companies are at risk as the economy slows down and their revenues decline, the rating company said in a report.

"Companies with weak business models face pressure on both revenue and on operating margins - calling cash-flow generation, or even survival, into question," Moody's analysts wrote in the report on 102 U.S. retailers.

Struggling retailers face the risk that suppliers might start demanding payments for shipments sooner, increasing their need for external financing. This financing might not be available because of tighter lending standards since the credit crisis hit last summer, the rating agency said.

This could lead to higher default rates and potential bankruptcies, Moody's analysts added.

While Blockbuster currently has sufficient liquidity to meet its cash obligations, the company is at risk of a potential covenant violation in 2009, according to Moody's.

Loehmann's has weak operating cash flow and has to rely on a revolving credit facility to finance free-cash-flow deficits. Both companies have the lowest Moody's speculative liquidity grade rating of SGL-4.

A speculative liquidity rating reflects the company's ability to generate cash internally and the availability of external funds relative to its cash obligations over the coming 12 months.

The rating agency cannot name other risky retailers because their ratings are not public, said Moody's senior analyst Ed Henderson.