Patent Due Diligence

What is patent due diligence?

Patent due diligence is the systematic review of a company's patent position conducted before a transaction — a venture financing, acquisition, IPO, license deal, or patent purchase. Its purpose is to verify that the patents the company claims to own (1) are actually owned by the company with clean, recorded chain of title; (2) are alive, with maintenance fees paid and deadlines met; (3) actually cover the products and revenue the buyer is paying for; (4) are not encumbered by licenses, liens, co-ownership, or government rights that undercut their value; and (5) do not come packaged with infringement exposure — demand letters, litigation, or freedom-to-operate problems. Scope scales with the deal: a seed financing may involve a quick title-and-status check on a handful of applications; a strategic acquisition involves attorneys reviewing every assignment, file history, license agreement, collaboration contract, and litigation docket, often with technical experts mapping claims onto the target's products and competitors'. Outputs typically include a diligence report flagging defects by severity, which then drives deal mechanics: price adjustments, escrows and holdbacks, special indemnities, closing conditions requiring defects to be cured (missing assignments executed, fees paid, licenses consented), or — for serious title defects — walking away. For sellers and founders, the practical insight is that nearly every defect is cheaper to fix before the deal than during it, and some (a co-inventor who now refuses to assign) may be unfixable later.

What are the most common patent title defects found in diligence?

The recurring defects, roughly in order of frequency: (1) Missing inventor assignments — a named inventor (often a departed founder, early employee, or consultant) never executed an assignment. Ownership vests initially in inventors; without a written assignment the inventor personally retains an undivided share. (2) Future-tense assignment language — employment agreements saying 'agrees to assign' rather than 'hereby assigns.' Under Board of Trustees of Stanford University v. Roche (U.S. 2011), a future-tense promise can lose to a later present-tense assignment to a third party. (3) Unrecorded assignments — the assignment exists but was never recorded at the USPTO. Recording within three months protects against a later bona fide purchaser (35 U.S.C. § 261); unrecorded chains also make title verification slow and contested. (4) Broken corporate chains — patents assigned to a predecessor entity, a dissolved LLC, or a founder's prior company, with no follow-on assignment after restructuring. (5) Undisclosed co-ownership — a university, hospital, or collaboration partner owns an inventor's contribution under its IP policy or an ambiguous joint development agreement. (6) Consultant gaps — contractors who contributed to conception under agreements with no IP assignment clause (or only a work-for-hire clause, which covers copyright, not patents). (7) Security interests — patents pledged as collateral for venture debt, with liens recorded and never released after payoff. (8) Government funding strings — federally funded inventions carrying Bayh-Dole obligations (government license, march-in rights, US manufacturing preference for exclusive licensees) that were never disclosed or perfected. Each of these is curable at some stage — and dramatically harder once the counterparty knows you need the signature.

What is the difference between patent diligence for an investment versus an acquisition?

The questions are similar; the depth and the consequences differ. Venture financing diligence (seed through growth): investors primarily verify that the IP story supports the valuation thesis — the company owns what it claims (founder and employee assignments executed, no university or prior-employer claims hanging over the founders), the portfolio plausibly covers the product roadmap, and there is no undisclosed litigation. It is usually conducted by the investor's counsel from a checklist, on a timeline of days to a few weeks, and defects typically result in closing conditions (sign the missing assignments before wiring) or representation-and-warranty language rather than price changes. Acquisition diligence: the buyer is purchasing the asset, so the review goes claim-deep: file histories read for prosecution disclaimer and estoppel; claim charts mapping independent claims to the target's products and to competitors' products (for offensive value); every license, JDA, SRA, and standard-setting commitment reviewed for change-of-control, assignment, and FRAND obligations; lien searches; foreign counterpart status and annuity verification; litigation and PTAB docket checks; and FTO analysis on the target's products since the buyer inherits the infringement exposure. Findings move real money: purchase price adjustments, escrows and special indemnities tied to specific defects, carve-outs of problem assets, or abandonment of the deal. A third variant — patent portfolio purchases (buying patents without the company) — focuses almost entirely on title, validity, remaining term, encumbrances (existing licenses travel with the patents), and enforceability, since there is no operating business to evaluate.

Why do unpaid maintenance fees and entity status errors matter in diligence?

Because both can quietly kill or cloud patents that look alive on a schedule. Maintenance fees: US utility patents require fees at 3.5, 7.5, and 11.5 years after grant; missing the fee (plus the 6-month surcharge window) makes the patent expire. Expired-for-nonpayment patents can be revived by petition only if the delay was 'unintentional' (37 C.F.R. § 1.378) — and a deliberate decision to let a patent lapse, later regretted, does not qualify. Diligence teams pull PAIR/Patent Center records to verify every fee on every asset; foreign annuities (due annually in most countries) get the same treatment. Intervening rights can also attach: someone who began practicing the invention while the patent was expired may have defenses even after revival. Entity status: the USPTO charges small entities 50%-reduced fees (roughly: under 500 employees, no obligations to license to large entities) and micro entities 80%-reduced fees (small entity + income and filing-count limits). Claiming a discount you are not entitled to — common after a startup signs a license with a large company (which destroys small entity status) or simply grows — and paying reduced fees can, if done with intent to deceive, render the patent unenforceable, and at minimum requires correction with fee deficiency payments. Diligence flags any portfolio where entity status doesn't match the company's history of size and licensing. Both issues are cheap to fix proactively (pay the deficiency, correct the status) and expensive to discover in a data room.

What should a startup do to prepare for patent due diligence?

Run the diligence on yourself before anyone else does. The preparation sequence: (1) Build and maintain an IP schedule — every patent, application, and material invention disclosure with status, jurisdictions, inventors, assignment recording details, and upcoming deadlines. (2) Audit assignments — for every named inventor on every asset, confirm an executed, present-tense, recorded assignment exists. Close gaps immediately; departed inventors get harder to find and more expensive to sign every year. (3) Verify procedural health — maintenance fees and foreign annuities current, entity status correct, foreign filing licenses obtained where inventions were made in the US, no silently abandoned applications. (4) Map claims to products — for each significant patent, a short chart showing which independent claims cover which shipping products. This is also when you discover the claims cover the 2021 prototype but not the current architecture — while there is still time to file continuations. (5) Assemble the contract file — every JDA, sponsored research agreement, consulting agreement, government grant, inbound and outbound license, and any standards-body participation, organized and summarized for change-of-control and exclusivity terms. (6) Document the disclosure timeline — every public disclosure (launches, papers, pitches, crowdfunding) relative to priority dates, with the grace-period analysis done. (7) Resolve known co-ownership — negotiate co-ownership agreements covering licensing consent, revenue, and enforcement cooperation before a deal gives the co-owner leverage. Companies that show up with this package shorten diligence by weeks, avoid escrows tied to IP defects, and signal operational maturity that itself supports valuation.