IBM secured 3,148 patents in 2007, besting all other competitors for the 15th consecutive year, but Big Blue's lead is getting slimmer and Microsoft charged into the top 10 with 1,637 patents, according to an analysis that will be released Monday.

Microsoft, which ranked No. 6 on the annual list after failing to crack the top 10 the previous two years, was one of only five companies to achieve even half of IBM's total patent output, according to IFI Patent Intelligence, a Wolters Kluwer Health business.

IBM has flexed its muscle in numerous patent disputes, winning a cash settlement from Amazon last May after claiming Amazon used IBM technology to build many of its e-commerce systems. Earlier this month, IBM convinced the U.S. government to investigate Asustek, a Taiwanese computer vendor accused of using IBM technology without authorization.

While Big Blue led all comers by well over 1,000 patents in 2005 and 2006, IBM finished 2007 with only 423 more patents than second-place Samsung Electronics. Nationwide, there were 9.5% fewer patents issued than in the record year of 2006, when the United States granted 173,772 patents, including 3,651 to IBM.

Samsung and Microsoft were among only five companies in the top 25 that secured more patents in 2007 than in 2006.

The U.S. Patent and Trademark Office faces a backlog of more than 1.1 million patents pending. In addition to the growing backlog, the office has been criticized for issuing questionable patents, including one in 2005 for an antigravity device. IBM and Microsoft are among those supporting broad changes to the U.S. patent system.

The patent office did receive a 9% budget increase for 2008, which could help alleviate the backlog.

"While 2007 didn't bring any marked improvements in terms of reducing America's backlog of patents pending, it wasn't far off the annual average of the past seven years either," Darlene Slaughter, general manager of IFI Patent Intelligence, says in a news release. "Although the total number of patents issued is down from 2006's record high, it did beat 2005's relatively low showing. Overall, it's fair to say that 80% of the top 35 organizations were down vs. the previous year."

After IBM and Samsung, the top 10 patent winners were Canon, Matsushita, Intel, Microsoft, Toshiba, Sony, Micron, and HP.

While U.S. companies comprise half of the top 10, Japanese firms account for 13 of the top 25. Semiconductors were the most-patented technology in 2007, with 4,187 patents, followed by 3,855 for active solid state devices and 2,783 for telecommunications.

Top performing areas also include static information storage and retrieval, drugs and biotechnology, chemistry, and radiant energy, according to IFI Patent Intelligence.

Here's the full top 25 list from IFI:

1. INTERNATIONAL BUSINESS MACHINES CORP, 3,148 patents

2. SAMSUNG ELECTRONICS CO LTD KR, 2,725

3. CANON K K JP 1987

4. MATSUSHITA ELECTRIC INDUSTRIAL CO LTD JP, 1,941

5. INTEL CORP, 1,865

6. MICROSOFT CORP, 1,637

7. TOSHIBA CORP JP, 1,549

8. SONY CORP JP, 1,481

9. MICRON TECHNOLOGY INC, 1,476

10. HEWLETT-PACKARD DEVELOPMENT CO L P, 1,470

11. HITACHI LTD JP, 1,397

12. FUJITSU LTD JP, 1,315

13. SEIKO EPSON CORP JP, 1,208

14. GENERAL ELECTRIC CO, 914

15. INFINEON TECHNOLOGIES AG DE, 856

16. DENSO CORP JP, 803

17. TEXAS INSTRUMENTS INC, 752

18. RICOH CO LTD JP, 728

19. HONDA MOTOR CO LTD JP, 719

20. SIEMENS AG DE, 700

21. LG ELECTRONICS INC KR, 684

22. NOKIA AB OY FI, 682

23. SHARP K K JP, 667

24. FUJIFILM CORP JP, 662

25. NEC CORP JP, 617