Neiman Marcus Group, Saks and Nordstrom had their debt ratings cut by Moodys’ Investors Service after luxury retail sales plummeted in recent months.

Neiman Marcus’s ratings were lowered the most, by three notches. Moodys’ predicted more poor operating results and weakening credit metrics for the privately held retailer as the luxury market contracts.

The high-end department stores have been reeling from steep sales declines as consumers have reduced purchases of discretionary goods.

Neiman Marcus’s operating results will continue to be poor and deteriorating credit profile as it approaches the expiration of its revolving credit facility in 2010, Moody’s predicted.

New York-based Saks rose 8 cents, or 4.4 percent, to close at $1.90 in NYSE trading. Nordstrom rose 68 cents, or 4.4 percent, to $15.71.