The USPTO has released its reexamination statistics through the third quarter of its fiscal year. Both ex parte and inter partes filings are on track for record totals, with a large increase seen in inter partes filings.

Through June 30, 2007 (the end of the third quarter), the USPTO received 477 ex parte reexamination filings. Only 340 requests had been filed by the same time last year. This represents a 40% increase.

The gains are even larger for inter partes reexamination. Through June 30, 2007, 90 inter partes reexamination requests were filed as compared to 40 requests by the same time last year. Indeed, the 90 requests filed through the first three quarters of fiscal year 2007 is more than the 70 requests filed for all of fiscal year 2006.

The increase in inter partes reexaminations is particularly surprising given the risk of litigation estoppel. 35 USC 315(c). The estoppel precludes the requester from later asserting in litigation the invalidity of a claim on any ground which it raised or “could have raised” during the reexamination. Concern about the estoppel has limited the use of inter partes reexaminations in the past.