Provisional Patent Applications: Waiting to File Non-Provisionals

For better or worse, provisional patent applications have always been used as a way to delay patent prosecution. The procedure has become popular as a relatively cheap and informal mechanism for preserving priority of invention without losing patent term. Although a provisional application sets a priority date, the application does not even reach the examination queue until the full utility patent application is filed. Thus, on average, each day of delay in filing the utility patent application pushes the issue date back one day as well. However, provisional applications also serve as a mechanism for extending the tail end of the patent term because the twenty-year patent term does not begin to run until filing of the utility patent.

Provisional applications have become quite popular. In FY2007, for instance, over 132,000 provisional applications were filed and about 30% of recent patents assigned to US companies reference a provisional filing. [Link]

To see how provisional filings are being used, I compiled a set of 65,000 patents that issued sometime between Jan 2007 and Feb 2009 (inclusive). All the patents in the group share the common property of claiming priority only to one or more provisional applications. I additionally excluded patents that made other priority claims such as continuations, divisionals, and continuations-in-part. Once I formed the set of patents, I then looked at the filing date of the provisional application compared with the filing of the utility application to how applicants are using the extra year of deferred examination. For patents claiming priority to multiple provisional applications, I used the date of the earliest filed provisional application.

The graph below shows the result. The vast majority of applicants wait until the year is almost up before taking action and filing the non-provisional application. About two-thirds of the non-provisional applications were filed with less than ten days remaining in the one-year provisional pendency. In over ten percent of the cases, applicants properly filed the non-provisional more than 365 days after the original provisional filing because of weekends, holidays, and/or leap year.


Two weeks ago, I had a conversation with a patent litigator about the propensity of patent attorneys to barely meet deadlines. He was worried about the potential for malpractice claims against his firm. And, here, I found a surprising number of cases that appear to miss the deadline.

My lingering question for patent attorneys and applicants — why delay so long? Is it simply a matter of doing work according to deadline? Does it matter that delaying filing the application also delays the eventual issuance of the patent?