Are provisional patent applications public or are they kept confidential?
All patent applications received at the US Patent Office are kept secret by the Patent Office. The most commonly
occurring exception to this rule is that when a patent issues, the application file becomes public. (Note that the
entire application file becomes public, not just the issued patent itself.) Another exception is that if a patent
application is referred to by number in an issued patent, the application file becomes public. This is the case for
both provisional applications and regular applications under 37 CFR § 111(a).
It has been proposed that the US Patent Office would change its rules on secrecy to be more like the rest of the
world. In most countries other than the US, a patent application becomes public 18 months after the priority date.