A.  Overview of Continuation-in-Part (CIP) Applications.

continuation-in-part (CIP) patent application is a patent application that claims priority to a Prior Application A that adds new subject matter to create CIP Application B.  For example, if Prior Application A filed on January 1, 2020 discloses features A, B, C and D, a continuation-in-part (CIP) Application B filed on March 1, 2021 would also disclose improvement features A, B, C and D plus additional features E and F.  Technically speaking, any claims in CIP Application B that are directed to only features A, B, C and D would be entitled to the January 1, 2020 filing date and any claims that include any of features E and F would only be entitled to the March 1, 2021 filing date.

When you have an improvement to an invention disclosed in a prior filed application, your options are to either file a new application or a continuation-in-part application.  Below is a quick summary of the benefits and detriments of filing a continuation-in-part application.

B.  Benefits of a Continuation-in-Part (CIP) Application.

If you file a new patent application, you will have two separate families of patent applications to prosecute and manage.  This can result in additional expenses at the USPTO and with your patent prosecution counsel.  Filing a CIP application instead of a new application allows you to streamline your patent prosecution to a single family of patent applications thereby resulting in lower costs. 

Below is a summary of the benefits of filing a continuation-in-part (CIP) application:

  • Lower Patent Prosecution Costs.  There are many benefits to keeping at least one patent application pending for any important product by filing a series of continuation applications (see Reasons to File Continuation Patent Applications).  By using a CIP application, you are able to file a single continuation application at a time to keep prosecution open for the original design and the improved design for your product.  If you filed a new application, you would potentially have to have two continuation applications pending all of the time which increases patent prosecution costs.
  • Lower Patent Management Costs.  With a CIP application, you are usually condensing your patent portfolio to a single series of patent applications which results in fewer patents to manage and maintain via patent maintenance fees.
  • Cost Effectively Reserve Right to Protect Original Design Features.  Sometimes the original patent application has features the client has decided not to use in the improved final product.  However, sometimes a competitor may avoid infringement upon a new application for the improved product but could be infringing upon claims directed at the original design.  Instead of abandoning the original patent application for the original design, a CIP application allows the client to keep the original design features in the patent application which allows the client to seek patent protection on the original design features at a later date if they want.
The main benefit of a continuation-in-part application is cost savings as discussed above.  As with anything in life, you get what you pay for so there are some tradeoffs when saving money using a continuation-in-part application as discussed below.

D.  Detriments of a Continuation-in-Part (CIP) Application.

While cost savings are important to clients, there are a detriments to filing a continuation-in-part (CIP) application that you should be aware of such as (not exhaustive):

  1. Loss of Patent Term.  A U.S. patent has a term of 20 years from the earliest effective filing date and then it automatically expires.  In the example above, Patent A that is granted from Prior Application A would expire on January 1, 2040 (January 1, 2020 Filing Date + 20 Years = January 1, 2040).  Patent B that is granted from CIP Application B would also expire on January 1, 2040 because it has the same earliest effective filing date as Prior Application A (i.e. January 1, 2020) because CIP Application claims priority to Prior Application A.  However, if you would have filed a new application instead of a CIP application the effective filing date for New Application B would be March 1, 2021 so Patent B would not expire until March 1, 2041a patent term gain of 15 months by filing a new application compared to filing a CIP application!
  2. Prosecution History Disclaimer.  Prosecution history disclaimer occurs when a patent applicant makes a clear and unambiguous disavowal of claim scope which can negatively affect the scope of patent protection in a patent application.  A CIP application may be subject to any any prosecution history disclaimers made in a prior application the CIP application claims priority to which in effect may narrow the scope of patent protection in the CIP application.
While cost savings are the main advantage of a CIP application, a patent application must consider the tradeoffs of the loss of patent term and the potential for prosecution history disclaimer from the original application.

E.  CIP Application v. New Application.

Many patent applicants ask if they should file a continuation-in-part (CIP) application or a new application.  The main benefit of filing a continuation-in-part application is cost savings (patent prosecution and managing patent portfolio) but there are potential detriments with file history estoppel as discussed above that should be seriously considered prior to doing a CIP application. 

Generally speaking, if you have a large patent budget and the technology is valuable to your business, it is usually better to file a new application instead of a CIP application.  Filing a new application prevents the loss of patent term and prosecution history disclaimer from the prior application.  Also, if the loss of patent term will be significant, then you would want to file a new application also to prevent the patent on the improvements from expiring too early.

However, if you are on a limited patent budget and/or the technology is not valuable to your business, then you should discuss filing a CIP application with your patent counsel to see if the CIP application cost benefits are worth the loss of patent term and potential prosecution history disclaimer detriments.

There is no perfect answer, but you can make the decision that makes sense for you at the time by working closely with your patent counsel.