New patent lawsuits hit an all-time high in November, with many plaintiffs likely hoping to avoid new pleading rules that came into effect yesterday. A whopping 790 lawsuits were filed last month, with at least 212 filed on a single day: Monday, November 30.

For those who watch the patent landscape, it will come as no surprise that most of the lawsuits filed last month come courtesy of "patent trolls"—oddly named LLCs with no business other than litigation. Also no surprise: a big majority of the cases were filed in Eastern Texas.

The huge jump, and in particular the November 30 spike, is likely tied to significant changes in the Federal Rules of Civil Procedure for patent cases, which took effect on December 1. The changes by the Judicial Conference of the United States may require patent plaintiffs to provide more information in their lawsuits to survive a motion to dismiss. For now, the lenient "Form 18" has been eliminated in patent cases. That form allowed patent lawsuits to be filed without naming which specific claims were infringed, or naming a specific product accused of infringing. It isn't clear what standard will replace the form.

"Although it's not unusual to have an end of the year uptick, one like this is certainly unusual," said Brian Howard, data officer for IP analysis firm Lex Machina, which provided Ars with some of its data about the November filing surge.

Howard also compiled a list of all the companies that filed 10 or more patent lawsuits in November. With the exception of pharmaceutical giant AstraZeneca, all the companies appear to be patent-holding shell companies. November's most litigious company was CryptoPeak Solutions, a company claiming HTTPS web encryption infringes its patent.

Looking at the statistics on a per-week basis, the final two weeks of November come in second and third place. The most patently litigious week was April 20, 2014—that week, patent trolls were rushing to beat another deadline, as rumors persisted that a patent reform bill would apply changes to that particular date. No such bill passed Congress, however.

A search of PACER, the public courts database, shows that of 249 cases filed on November 30, a stunning 195 of them—nearly 80 percent—were filed in the patent-friendly Eastern District of Texas. Just about all of the Eastern District cases are filed by LLCs that appear to be patent-holding companies. For the full month, a PACER search shows that 470 out of 829 cases, or about 56 percent, were filed in East Texas.

A note on the data: The PACER search numbers differ from the Lex Machina numbers, because Lex Machina eliminates things like "false marking" lawsuits and certain incorrectly marked cases. It also takes two to three days to fully pick up the data, so their figure for Nov. 30 is likely to rise.