FORTUNE — Wireless carrier AT&T (T) was the top target of so-called patent trolls in 2013, having been sued more than 54 times by them in 2013—more than once a week. This year’s list of top ten patent troll targets was published today in a Fortunemagazine feature story about RPX Corp.(RPXC), which compiled the statistics.
The article, called “Taking on the Trolls,” states: “AT&T is no anomaly. Google (GOOG) was hit with 43 [such] suits last year; Verizon (VZ), 42; Apple (AAPL), 41; Samsung (SSNLF) and Amazon (AMZN), 39 each; Dell and Sony (SNE), 34 each; Huawei, 32; Blackberry (BBRY), 31. Every brand on this unenviable top-ten list was sued by [a patent troll] at least once every 12 days.”
“Patent troll” is a pejorative term. A more neutral term, and the one that RPX uses, is “non-practicing entity,” or NPE. An NPE is a company that sells no products or services of its own. In their most controversial form, NPEs purchase patents on the open market and then assert them against operating companies, like AT&T and Google, seeking licensing fees and, often, suing to get them.
RPX is what’s known as a defensive patent aggregator. In exchange for a subscription fee—currently paid by some 168 companies, including Google, Verizon, and Samsung—it attempts to buy up potentially problematic patents on the open market, before NPEs can get their hands on them.
According to RPX’s statistics—which have been relied upon by academics and government agencies—NPEs filed 3,608 new suits in 2013, up 19% from the 3,042 they filed in 2012, and their suits named 4,843 total defendants, up 13% from the 4,282 sued a year earlier. NPE suits accounted for 67% of all new patent cases filed last year, and 63% of all new patent defendants, according to the figures RPX shared with Fortune.
When one takes into account NPE cases filed in previous years and still unresolved as of December 31, 2013, the top NPE target was Google, which was fighting 72 active cases as of that date. The next nine companies in line after it were AT&T (70), Apple (68), Samsung (63), Sony (58), Amazon (54), Verizon (46), HTC (42), LG Electronics (42), and Dell (41). (The figures for Google include suits against its Motorola Mobility unit, which Google announced last month that it is selling to Lenovo (LNGVY).)
NPEs have their defenders, as the Fortune story explains: “These argue that giant tech corporations routinely pilfer innovations dreamed up by independent inventors, and that NPEs simply give these powerless individuals the financial support and litigation muscle they need to vindicate their rights. NPEs therefore serve not only small inventors, the argument continues, but also society at large, by preserving the incentive systems that our Founding Fathers wrote into the Constitution to ensure that the Thomas Edisons of the world would be motivated to provide the rest of us with the maximum possible benefit from their genius.
”Still, the sheer numbers have many people skeptical. Is AT&T really stealing breakthrough ideas from various Edisons at a rate of more than once a week?”