WASHINGTON — More than 40 percent of patent lawsuits are filed in a federal court in East Texas with a reputation for friendliness to plaintiffs. That curious fact was the backdrop for a Supreme Court argument on Monday over whether the court should halt what many big technology companies say is pernicious forum shopping in patent cases.

In recent years, a single judge based in Marshall, Tex., oversaw about a quarter of all patent cases nationwide, more than the number handled by all federal judges in California, Florida and New York combined.

The Texas court is a favorite venue of patent trolls, or companies that buy patents not to use them but to demand royalties and sue for damages. Many tech companies filed supporting briefs in Monday’s case, TC Heartland v. Kraft Foods Group Brands, No. 16-341, urging the Supreme Court to limit the places where defendants in patent cases may be sued.

But a few companies urged the justices to retain the current rules, saying there was a value in letting cases be considered by courts that have developed expertise in patent matters. And some pharmaceutical companies said they should be able to sue the makers of generic drugs all at once in a single court.