The U.S. Patent and Trademark Office in Alexandria, Va. (AP Photo/Alex Brandon)

For months, Congress has moved steadily toward a bill that targets patent trolls — companies that own patents but don't make any products with them. The problem, critics say, is that the patent holders will sue innocent companies in hopes they'll simply settle for a bunch of cash. But even as firms like Etsy and Kickstarter hit Capitol Hill this week to press the case against abusive patent lawsuits, a new study shows that the pace of litigation has actually slipped — for the first time in five years.

This is a big deal for a whole range of industries, not just the tech sector. It's happening at a time when the spotlight on frivolous patent lawsuits has never been brighter. And that makes it a surprising find.

Here's the key chart from PricewaterhouseCoopers' latest report on patent litigation. The line in gray shows the number of new patent lawsuits that were filed each year.


(PwC)

You can see that in 2014, there was a sharp drop in the number of new patent cases. There were about 5,700 filed last year, according to PwC. That might sound like a lot, but it's actually a 13 percent drop from the year before. We haven't seen anything like this since 2009 — which is about when many companies started getting hit with their first demand letters.

The letters are often vague about which patents have allegedly been infringed, leading to confusion and fear among the victims about what they may have done wrong. They can fight the suit and go to court, but defending a case is costly and unaffordable for many companies. The congressional legislation being debated would try to address some of these issues.

[Is 2015 the year Congress finally takes on patent trolls?]

But here's what else could wind up curtailing patent litigation: The Supreme Court. According to PwC, the sharp decline in new patent lawsuits can be traced almost directly to the outcome of a major case last year known as Alice Corp. v. CLS Bank. Most analysts at the time said that Alice didn't matter much. The Court ruled that the software patent Alice Corp. used to sue CLS didn't pass the smell test. That much was obvious to many people watching the case; what they really wanted from the Court decision was a more concrete outline as to what kinds of software patent were patentable.

But the fact that Alice put some limits on software patents at all appears to have put major pressure on those who are considering bringing a patent lawsuit, said PwC.

Alice effectively "raised the bar for patentability and enforcement of software patents," PwC's report reads.

This doesn't make the issue of abusive patent litigation go away. Previously, PwC found that patent trolls accounted for 67 percent of all new patent lawsuits. But this year's findings suggest that the increase in patent trolling is not inevitable.