Neiman Marcus Group Inc. is suing a pair of domain name companies, accusing them of improperly registering more than 40 Internet addresses that resemble the department store chain's trademarks.

The lawsuit accuses the companies of domain name tasting, or taking advantage of a five-day refund period to sample which of the addresses might generate traffic — and thus potential ad revenues, before committing to buying them.

Name.com LLC and Spot Domains LLC, two Denver-based companies that share offices and employees, were named as defendants. The companies told The Associated Press on Friday they do not comment on pending litigation.

The complaint, filed last week in U.S. District Court in Denver, seeks injunctions and damages of at least $100,000 per name.

The lawsuit comes weeks after Neiman Marcus settled a similar lawsuit against Dotster Inc., in which Neiman Marcus accused the registration company of tasting hundreds of names meant to lure Internet users who mistype Web addresses.

At one point, the lawsuit said, the misspelled NeimuMarcus.com featured ads for Target, Nordstrom and other rivals.

As part of the settlement, Dotster agreed to stop registering names similar to Neiman Marcus or sister chain Bergdorf Goodman. The registration company also agreed to suspend use of automation to register domain names in bulk.

Experts estimate that up to 6 million names are tied up at any given time through domain name tasting, thanks to computer automation and a burgeoning online advertising market.

The practice takes advantage of a grace period originally designed to rectify legitimate mistakes, such as registrants mistyping the domain name they are about to buy.

During the grace period, registrants generally put up a generic search site with advertising and keep the ones that might make more than the $6 annual cost of a name.

Neiman Marcus isn't alone in fighting back.

Earlier this month, Microsoft Corp. (MSFT) filed a lawsuit in U.S. District Court in San Francisco against Mountain View, Calif.-based Maltuzi LLC, which, according to its Web site, registers large numbers of Web domain names using automated processes, and profits from ads placed on those pages.

Maltuzi did not return an e-mail seeing comment, but its Web site says, "We deliberately exclude registered trademarks and known common law trademarks from our buying program."

Microsoft filed another suit, in Seattle, naming as defendants unknown "John Does." Lawyers often use such suits as the basis for obtaining identities through subpoenas and other means.