Continuation vs Continuation-in-Part vs Divisional: What Is the Difference?

What They Have in Common

All three are child applications in the same patent family. Each must be filed while the parent application is still pending, a requirement called copendency, and each must contain a specific reference to the parent to claim the benefit of its filing date under 35 U.S.C. § 120. For applications filed on or after September 16, 2012, that benefit claim goes in the application data sheet, generally within the later of four months from the child's filing date or sixteen months from the parent's filing date.

None of them extends the life of the family. Under 35 U.S.C. § 154(a)(2), a utility patent's term ends twenty years from the earliest non-provisional filing date to which it claims benefit under § 120 or § 121, adjusted by any patent term adjustment earned in its own prosecution.

Continuation

A continuation repeats the parent's disclosure without adding new matter and presents a different set of claims. Every claim receives the parent's effective filing date, provided the parent's disclosure supports it.

Continuations are used to:

• Pursue broader claims after accepting narrower claims in the parent
• Draft claims that read on a competitor's product once it reaches the market
• Keep a family pending so that new claim strategies remain available

Because a continuation often claims obvious variants of the parent's claims, examiners commonly issue nonstatutory, or obviousness-type, double patenting rejections. These are usually resolved with a terminal disclaimer, which ties the continuation's expiration to the parent and requires common ownership for enforceability.

Continuation-in-Part

A continuation-in-part, or CIP, repeats some or all of the parent's disclosure and adds new matter. The result is a mixed application. Claims fully supported by the parent's disclosure receive the parent's filing date. Claims that rely on the new matter receive only the CIP's own filing date, so anything published or sold in the meantime can be prior art against them.

That split creates a term penalty. The CIP's term still runs from the parent's filing date, so claims directed to the new matter receive less than twenty years of effective protection from the date they were first filed. For that reason, many practitioners file a new, independent application for a significant improvement, claiming priority where available, rather than a CIP.

Divisional

A divisional is filed to pursue claims the applicant did not elect after a restriction requirement. It has the same disclosure as the parent, and all of its claims receive the parent's filing date.

Its main advantage is the safe harbor in 35 U.S.C. § 121: a patent issuing on an application filed as a result of a restriction requirement cannot be used as a reference against the divisional, or the parent, in a double patenting rejection. The protection applies only if consonance is maintained, meaning the divisional's claims stay within the lines of the restriction. Claims that drift back toward the elected invention can lose the safe harbor. The Federal Circuit has held that the safe harbor does not extend to continuations or continuations-in-part, so the child application should be designated and prosecuted as a divisional.

Choosing Among Them

• New claims, same disclosure: file a continuation.
• Claims the examiner restricted out: file a divisional to preserve the § 121 safe harbor.
• New technical content: consider whether a CIP or a new application better serves term and priority, remembering that new matter never receives the parent's date.

In each case, file before the parent issues or is abandoned. Once the parent's issue fee is paid, there is a short window before the patent issues, and a missed window cannot be recovered.

Planning Family Strategy

Deciding when a family should stay open is a portfolio decision as much as a prosecution one. ArcPrime's continuation recommendations identify pending families where a continuation could pursue claims that read on products in the market.