Investor due diligence on a patent portfolio: what gets checked and how to prepare
In patent due diligence, investors check five things: chain of title (every inventor has assigned to the company and the assignment is recorded), correct inventorship, whether the claims cover the product actually sold, status and upcoming deadlines for every application, and encumbrances such as licences, liens, or university rights. Missing inventor assignments are the most common defect found.
- Funding effect: startups holding both patents and trade marks at seed or early stage are up to 10.2 times more likely to secure funding (EPO and EUIPO, 2023)
- Seed stage: companies with granted or pending patents are 2.9 times more likely to obtain seed funding than those with no IP rights (EPO and EUIPO, 2023)
- Ownership rule: in the US a patent right vests initially in the inventors, so an inventor who never signed an assignment retains an undivided share (USPTO on patent assignment)
- Exit effect: filing patents and/or trade marks is associated with a more than twice higher likelihood of a successful exit for investors (EPO and EUIPO, 2023)
- Related reading: what to do with patents when raising money or selling the company (Lightbringer)
What due diligence is actually testing
Investors are not counting patents. They are testing whether the company owns what it says it owns, whether that protection covers the business they are pricing, and whether anything in the paperwork could let a third party take a share of it. A portfolio of three well-owned, well-mapped applications passes; a portfolio of 20 with one unassigned co-founder does not.
The five checks
- Chain of title: a written assignment from every named inventor to the company, recorded at the USPTO Assignment Center or the equivalent office, with no residual interest left behind and no security interest registered against the assets
- Inventorship: the named inventors match who actually contributed to the claims, not who worked on the product. Missing or extra inventors are a validity risk in the US
- Claim scope against the product: counsel reads the independent claims against the current product and roadmap. Claims that cover a 2022 prototype and not the shipped system are a red flag, not an asset
- Status and deadlines: every application's stage, the next office action or national phase deadline, and maintenance fees paid on grants. A lapsed application in the schedule raises questions about how everything else is run
- Encumbrances: licences in or out, university or prior-employer rights, government funding conditions, co-ownership, and any lien from an earlier lender or investor
The defects that reprice rounds
The recurring one is the departed inventor: a co-founder, early engineer, or contractor who is named on an application and never signed an assignment. In the US, ownership vests in inventors, so that person personally holds an undivided share until they sign. When they are cooperative it is paperwork; when they left badly it is a negotiation that happens on the investor's clock. Close behind are inventions developed while a founder was still employed elsewhere, and university spin-outs where the licence terms restrict the field or the exclusivity.
How to prepare before the term sheet
Build the IP section of the data room in advance and keep it current: a schedule of every patent and application with jurisdiction, status, and next deadline; a recorded assignment for every inventor on every family; employment and contractor agreements with present-tense IP assignment clauses; every licence and university agreement; and a one-page map from each asset to a product or roadmap item. Investors read the map first, because it shows whether the portfolio was built on purpose.
Why it matters for the raise itself
The EPO and EUIPO found that European startups holding both patents and trade marks at seed or early stage are up to 10.2 times more likely to secure funding, and that companies with granted or pending patents are 2.9 times more likely to obtain seed funding than companies with no IP rights. Diligence is where that advantage is either confirmed or lost.
What most founders get wrong
- "Patent pending" as the whole answer: investors read the claims, not the status
- Assignments in a drawer: signed but not recorded assignments still show a gap in the public register
- No product map: a portfolio with no link to revenue reads as legal spend, not strategy
- Starting at the term sheet: chasing a former contractor for a signature during a 30-day diligence window is the worst time to discover the gap
How Lightbringer prepares portfolios for diligence
Lightbringer is the AI-native patent service for tech companies: patents drafted with purpose-built AI, reviewed and filed by Lightbringer's own patent attorneys, for one flat fee per application.
Every application drafted on Lightbringer is tied to a disclosure that records who invented what, so inventorship is settled before filing and the assignment paperwork starts from a clean record. The platform holds status and deadlines for every application in one place, so the schedule investors ask for is an export, not a project. Lightbringer's attorneys can also review an existing portfolio ahead of a round. Pricing is the Starter plan at $7,200 per patent application per year, official fees separate.
Frequently asked questions
Ownership. They verify that every named inventor has signed an assignment to the company and that the assignments are recorded at the USPTO or the relevant office. A missing assignment from a departed co-founder or contractor is the most common defect and can stall or reprice a round.
Yes, but they are weighed differently. Investors and their counsel look at whether the pending claims are likely to grant and whether they cover the current product. A provisional with no follow-on filing, or claims drafted around a prototype no longer in production, adds little.
Build the data room before the term sheet: a schedule of every patent and application with status and deadlines, recorded assignments for every inventor, employment and contractor agreements with IP clauses, any licences or university agreements, and a one-page map from each asset to a product or roadmap item.
The EPO and EUIPO found that European startups holding both patents and trade marks at seed or early stage are up to 10.2 times more likely to secure funding, and companies with granted or pending patents are 2.9 times more likely to obtain seed funding than those with no IP rights.
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