With the exception of national security stuff, US patents are now published one year after application. http://robertplattbell.blogspot.com/2009/01/prior-art-s

With the exception of national security stuff, US patents are now published one year after application. http://robertplattbell.blogspot.com/2009/01/prior-art-searches.html http://robertplattbell.blogspot.com/2009/01/prior-art-search... If a Patent is "pending" it is kept secret for 18 months, then it might be published. Some are not published (it is an opt-out system) others filed under the old rules (pre 2001) are not published, period. So it is possible that a patent may be "pending" that you don't know about. If this product has been on the market for several years, the likelihood of it being "pending" diminishes accordingly. But some Patents take 5, 6 or more years to issue. So you may never have a concrete answer whether one of your competitors has filed for a patent or not. Additionally, a patent can be reserved, almost two years before filing, by the following sequence: 1. Perform an Invention Disclosure before a credible witness. 2. Wait almost one year. 3. File a Provisional Application for Patent. 4. Wait almost one year. 5. File an Application for Patent. So, normally, there could be 3.5 years of secrecy. If USPTO publication is opted-out, or if the filing was done under the pre-2001 rules, the secrecy term could be longer, possibly to infinity.