Due Diligence

DIY Due Diligence on Foreign Patents and Pending Applications

201701-lm-picA Continuation-In-Part –

In a recent issue of our column, we gave a lesson on performing “do-it-yourself due diligence” on a pending U.S. patent application.  This month, we present a “Continuation-In-Part” of sorts: how to perform basic DIYDD on pending international and foreign applications and issued patents.  Although in most instances, the basic information to be sought is the same (confirming existence of a patent or an application, prosecution status, and/or ownership), the exact steps vary from U.S. due diligence, mostly due to the structures of the websites and underlying databases available to search.

Our Sources

Depending on the definition of “country,” there are about 195 countries in the world. Of those countries, as of December 2016, 176 are members2 of The Paris Convention for the Protection of Intellectual Property, and 151 are members3 of the Patent Cooperation Treaty4.  “Paris” and “The PCT” are the two major treaties by which countries throughout the world cooperate to protect intellectual property, including patents.

Based on the membership of these treaties, there are probably about 180 Patent Offices worldwide that receive and process patent applications. Most of these are “national” Patent Offices, i.e. Offices of individual countries, but additionally, there are several “regional” Patent Offices, such as the European Patent Office (EPO), and the African Regional Intellectual Property Organization (ARIPO).  Of course, there is also the World Intellectual Property Organization, which administers the PCT, and also receives PCT applications via its International Bureau.

In our summary here, we will limit the tools we use to the Patentscope search site of WIPO, and the Espacenet search site of the EPO. This is partly due to our lack of fluency in more than 100 foreign languages, but more importantly, because the Patentscope and Espacenet search sites contain a considerable amount of information on patent application filings worldwide.  If you are fluent in one or more Asian languages, and are particularly interested in patents and pending applications in China, Japan, or South Korea, you may have good results searching directly on the websites5,6,7 of those foreign patent offices.  If you are interested in any other specific country, you may be able to access its Patent Office via the “Directory of Intellectual Property Offices” website8 of WIPO, which has links to the Intellectual Property and/or the Patent Offices of numerous foreign countries.

We also note that there are private sector commercial search sites available online, which presumably are “tapped in” to the databases of the USPTO, WIPO, EPO, JPO, KIPO, SIPO, and possibly other countries/regions. Good results may often be obtained from those search sites, once their particular “user interfaces” are understood.  Nonetheless, we will limit our summary to the use of the WIPO and EPO sites, and avoid endorsing any particular commercial site.

Your Situation

Suppose that you have an opportunity to acquire or invest in a company that has valuable technology, and the company’s IP strategy appears to include the pursuit of patents in foreign countries. You will likely be provided with some information on the company’s “patent portfolio,” which may vary from highly specific to highly vague. At the specific end, you may be given the numbers of issued patents or published applications.  In the middle, you might have a list of countries where patents have been issued or patent applications filed. At the extreme vague end, you may simply be told something like: “We have patents [or we are patent pending] worldwide.”

The first step in performing due diligence is to take inventory of what you know. In particular, make a list of “what, who, when, and where.”  The items on your list will serve as specific search criteria when you access the search sites.  Here are some key facts that you will want to list, if possible:


  • Any numbers that you have been provided. The numbers could be patent numbers, published application numbers, or patent application numbers of the particular Patent Office of their origin. For any given number, it is important that you know which one of the three numbers it is, because you may need to use it in a search field, and you must enter it in the proper field to obtain correct results.
  • List a small number of keywords or phrases that are descriptive of the invention or technology that is (allegedly) patented or patent pending. These may come in handy in a keyword search, alone or in combination with other criteria.


  • Identify the name of the company that would likely be listed as an Applicant on any issued patents or pending applications. Consider some possible variants of the name. Consider possible subsidiary names, LLC names, etc.  Do a “corporation” search on the database in the state of incorporation of the company to find a possible exact name that might be used in naming an Applicant in a patent or application.
  • If the company has any sort of research and development relationship with a university, be sure to include it in your Applicant names to be searched. Do a quick online or patent search to try to identify how the university is named as an Applicant or Assignee on any patents. (For example, you might find something unexpected, such as instead of “University of Nunda,” an Assignee is listed as “The Nunda University Research Foundation.”)
  • Consider who might be named as inventors in a patent or application. For small tech startup companies, they could be one or more of the founders of the company. Where there is a relationship with a university, they could be the professors and/or graduate students performing the research (and doing the inventing).


  • If possible, identify time limits for when the patent(s) or pending application(s) were issued, published, and/or filed. These limits may be useful for filtering results to narrow a search.


  • List the countries where the company’s technology is (allegedly) patented or patent pending. Look up the two-letter county codes for each country on the USPTO site9 (or on WIPO or Espacenet). They may be needed in a search field.
  • If the information from the company includes something to the effect of “patent pending internationally,” that suggests a PCT application. Plan to search the WIPO Patentscope site.

One Caveat

We note that with regard to due diligence on a particular patent application, as in our previous column, all of the suggestions here are contingent on the application being published so that information on the application is in fact accessible to the public. If the application was filed less than 18 months ago, or claims priority to an application filed less than 18 months ago, then even if you have an application number to search, it will not have been published and will be unavailable for access to the public.

First Stop: WIPO

Suppose you know that the company has a PCT application pending, or that you simply want to check that possibility. You should access the WIPO Patentscope search site, either the “Simple” site10, or the “Advanced” site11.  Although the Advanced site allows searching of combinations of multiple fields and complex Boolean strings, we prefer the Simple site, and typically obtain useful results quickly.  On the Simple site, before you search, click the Options tab, and in particular, be sure that your desired language is chosen, and that you also choose the “Office” to be searched.  (In Patentscope, WIPO’s search site, you can search for only PCT applications, or over a broader range of patent offices.)

“WIPO’s Patentscope and EPO’S Espacenet search sites contain a considerable amount of information on patent application filings and issued patents worldwide.”

Let’s assume that you only want to search PCT applications here, and that you will do a full “country” search on Espacenet, the European Patent Office’s search site, later, so only the “PCT” box is checked. Back at the Simple search page, choose a search option from the drop down menu.  “Front page” is usually a good choice, because that choice is for a search of the bibliographic information on the front page of a PCT application.  So whatever criteria that you want to choose from your inventory list, there is a good chance that it will produce hits on your search.

When you execute your search, if only a single PCT application is found, it will open the Bibliographic Data page for that PCT application. If there are multiple hits, it will produce a list of the PCT application titles, hyperlinked to their respective bibliographic pages.  From that point, you can review the list, and go to the biblio pages of those of interest.

Once you are at any given biblio page of an application of interest, study it carefully to be sure that the data there is consistent with what you would expect. On the biblio page, there are multiple additional tabs that will let you access the as-filed specification, drawings, and claims of the application.  Be sure to check the Documents page, which lists documents resulting from the filing and prosecution of the application, all available for downloading as pdfs.  Also check the National Phase page, which lists the countries in which national phase applications have been filed, which is where actual foreign patent protection is being sought.

Next Stop: Espacenet

For searching in the EPO search site, Espacenet, there are also the choice of simple (“Smart search”11) and Advanced search12.  In Espacenet, we prefer the Advanced search option because of the user friendly interface.  All of the useful search fields are listed with respective formatting examples and help (i) boxes immediately above them.  It typically only takes a couple of tries to “get the hang of” Espacenet and achieve useful results.

To perform a search on the Advanced page, enter one or more criteria from your inventory list in the appropriate fields. Keep in mind that if you are searching on keywords in the “Title or abstract” field, or on a corporate name in the Applicant field, you may find the use of Boolean strings, quotation marks, and/or wildcards to be effective in producing results.  The “Quick help” links on the left side of the web page will quickly get you up to speed on those.

If your search result is a single hit, or a list of hits, in either case, the application title(s) will be presented, hyperlinked to respective bibliographic pages. The bibliographic information presented in Espacenet, as well as the access to the specification, drawings, and claims of an application or patent is similar to that provided in WIPO’s Patentscope site, although it is in a different arrangement.  In the biblio list, the links provided at the “Also published as” line are particularly useful: those links go to any other foreign patent applications or issued patents that are within this “family” of applications, i.e., those that share the same priority application.  Another useful feature in Espacenet is its machine translation capability.  For the Abstract, Description, and Claims of the application, you can obtain a machine translation from the language of that application into the language that you want.

Reaching Conclusions

This column has focused more on how to track down information on issued foreign patents and pending international and foreign applications, and less on what to do with the information, once you have it on hand. We note that much of the information that we presented in our previous column1 on the analysis of U.S patent applications is also applicable to PCT and foreign applications and issued patents.  Thus a brief review of that column would likely be helpful in analyzing the results of your foreign due diligence searching.

  1. See The Limited Monopoly®, October 2016.
  2. www.wipo.int/treaties/en/ShowResults.jsp?lang=en&treaty_id=2.
  3. www.wipo.int/pct/en/pct_contracting_states.html.
  4. See The Limited Monopoly®, November 2007.
  5. www.sipo.gov.cn/.
  6. www.jpo.go.jp/.
  7. www.kipo.go.kr/kpo/eng/.
  8. www.wipo.int/directory/en/urls.jsp.
  9. http://patft.uspto.gov/netahtml/PTO/help/helpctry.htm.
  10. https://patentscope.wipo.int/search/en/search.jsf.
  11. https://patentscope.wipo.int/search/en/advancedSearch.jsf.
  12. https://worldwide.espacenet.com/.
  13. https://worldwide.espacenet.com/advancedSearch?locale=en_EP.

PHOTO CREDIT: “Tower Bridge, London, UK” by R.D. Gunderman.

To browse the entire searchable library of prior issues of The Limited Monopoly® from 2005 to present, visit www.thelimitedmonopoly.com.

Authors John M. Hammond P.E. (Patent Innovations, LLC www.patent-innovations.com) and Robert D. Gunderman P.E. (Patent Technologies, LLC www.patentechnologies.com) are both registered patent agents and licensed professional engineers.  Copyright 2017 John Hammond and Robert Gunderman, Jr.

Note: This short article is intended only to provide cursory background information, and is not intended to be legal advice.  No client relationship with the authors is in any way established by this article.