Reuters, based in London, is seeking "injunctive relief and damages" from Bloomberg in a federal court in New York.
The lawsuit claims that Bloomberg, founded by New York Mayor Michael Bloomberg, infringed three 17-year Reuters patents that cover so-called matching systems used by traders in the foreign exchange and equity markets, according to the Financial Times.
A report by Associated Press quotes a Reuters spokesman adding that the trading technology in question generated $88.4 million for Reuters last year.
"We're confident we have not infringed on the patents and in our judgment, the suit has no merit," Chris Taylor, a spokesman for Bloomberg, told the Financial Times.
Bloomberg, the owner of Bloomberg News, competes with Reuters in providing news, information and trading systems to the financial community.