The blue chip bank is concerned that the 'Goldmansex' domain name might be confused with its own.
Goldman Sachs has submitted a complaint about the site to the National Arbitration Forum (NAF), which is run by a man in The Netherlands.
The NAF mediates on corporate disputes, including those over internet domain names.
The Dutch site contains listings for strip clubs, escort agencies and other "objectionable adult material", not the kind of thing with which a venerable financial institution would want to be associated.
But Rob Muller, 32, who founded Goldmansex and is its sole employee, insists that 'Goldman' is his nickname. "People thought I was always lucky in my life," he told Cnet.
Muller has hired a lawyer and intends to fight to retain the domain name because he does not agree that it causes any confusion. "Would [Goldman Sachs] clients really think this is some sort of new product line?" he asked.
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