Case Study: M&A IP Due Diligence Case Study: A Battery-Storage Acquisition

This M&A IP due diligence case study follows a mid-market private-equity fund about to acquire a grid-scale battery energy storage systems (BESS) developer, in a sector where patenting is moving faster than almost anywhere else in clean energy. The fund’s thesis rested on the target’s ‘proprietary’ battery-management and cell-integration IP — so before the price was fixed, it needed to know whether the target actually owned that IP, what it was worth, and what about it could break the deal after close. This is what the diligence found.

The Challenge

The fund was buying the target largely for its intangibles. In grid-scale storage, the defensible value increasingly sits in the battery-management system, the cell-integration and thermal know-how, and the grid-interconnection patents — not in the commodity hardware. The board’s model assumed the target held that IP outright and could exclude rivals with it. Nobody had tested the assumption against the primary record.

The sector context made the stakes concrete. The EPO and IEA report that batteries now account for around nine in ten of all electricity-storage patents, and battery patenting has been growing far faster than technology as a whole — roughly 14% a year between 2005 and 2018, four times the all-field average. The EPO’s Patent Index 2024 recorded battery-technology filings rising a further 24.0% year on year. In a field filling that quickly, an unrecorded assignment or an encumbrance is not a paperwork detail — it is the difference between owning a defensible position and renting one.

The fund’s corporate-development lead wanted three things before the definitive agreement was signed: proof the target owned its headline families, a valuation range it could defend to the investment committee, and an early warning on anything that would break the thesis after the wire cleared. The diligence was scoped to the deal calendar — a fast screen during exclusivity, then a deeper title, valuation and red-flag pass through confirmatory diligence.

Our Approach

We ran the mandate through our standard M&A IP due diligence method, rebuilding the portfolio from the primary record rather than accepting the data-room schedule at face value. The work moved in four steps:

• Portfolio inventory — every live and pending patent family, registered mark and material trade secret, each tied to the exact legal entity on the filing, with assignee names normalised so a family sitting with a dormant subsidiary could not hide.
• Chain-of-title verification — each core family walked from the inventor’s original assignment through every corporate transfer to the entity signing the deal, reconciled against the recorded USPTO assignment database, not the target’s spreadsheet.
• Encumbrance and red-flag search — licences-out, liens and security interests, standard-essential or grid-interconnection commitments, and pending challenges such as IPR petitions or oppositions.
• Valuation range — the families that read on real revenue and exclude real competitors separated from the long tail, and priced against the deal rationale rather than book value.

The governing rule for the title work is 35 U.S.C. § 261: a patent assignment is void against a later good-faith purchaser for value unless it is recorded at the USPTO within three months of execution, or before that later purchase. That statute turns an unrecorded transfer from a clerical lapse into a live risk that the rights the target is selling can be cut off by someone who recorded first. So we tested every core family against the recorded record, not the narrative in the data room.

The same discipline extended past patents: trademark ownership was matched to the entity that would hold it post-close, contractor-built software was checked for written assignment rather than assumed work-made-for-hire, and the trade-secret claims were tested for whether the target had actually taken reasonable steps to keep them secret. Each is a place where a confident schedule and the enforceable reality quietly diverge.

We also ran a freedom-to-operate screen in the opposite direction — not what the target could exclude, but what it might infringe. A BESS product integrates cells, power electronics, thermal management and grid-interconnection firmware, each of which can read on a third party’s live claims. An infringement exposure running the other way is a liability the acquirer inherits at close, so it belongs on the same register as the ownership gaps. The screen tested the target’s flagship product against the densest clusters of live claims in battery management and grid interconnection.

Throughout, the assignee data was normalised before anything was counted. In a group that had grown by acquisition, the target filed under three different entity names and a legacy brand from an earlier deal, so a naive count of ‘the target’s patents’ both double-counted some families and missed others sitting with a dormant holding company. Reconciling those names to a single owner map is unglamorous work, but it is what makes the inventory — and every valuation and title conclusion built on it — trustworthy rather than merely tidy.

What the Research Found

The inventory rebuilt cleanly, but the title work surfaced the first and most expensive problem. Two of the target’s headline battery-management families — central to the ‘proprietary’ thesis — carried a broken chain of title. In one, a founding engineer who had since left had never executed an assignment to the company; in the other, a 2021 subsidiary reorganisation had moved the family between group entities without ever recording the transfer at the USPTO. On the recorded record, the entity being acquired did not cleanly own what it was selling.

The second red flag was an encumbrance the data room had not foregrounded: an exclusive license-out of a key cell-management patent, granted years earlier to a joint-venture partner. The technology the fund believed it was buying exclusively was, for a material field of use, already in someone else’s hands — and the licence travelled with the asset. Third, a grid-interconnection patent carried a standards-related commitment that capped what the acquirer could extract from it. Fourth, a cluster of peripheral families had lapsed for unpaid maintenance fees, inflating the schedule’s count without protecting anything.

Read together, the four findings changed the picture the model assumed. The count of families the target could actually convey, unencumbered and enforceable, was smaller than the schedule implied, and the ‘exclusive’ core was narrower than the thesis required. None of this was visible in the audited financials or the physical assets — it lived entirely in the register and the recorded assignment data.

The freedom-to-operate screen returned a fifth, quieter signal that fed the same conclusion. The target’s grid-interconnection firmware sat close to a third party’s live claims — not a confirmed infringement, but a residual risk the acquirer would carry, and one worth pricing into the indemnity rather than discovering in a demand letter after close. It was a reminder that diligence has to look both ways: at what the target owns, and at what it may owe.

The Outcome

The findings became direct inputs to the negotiation rather than a report filed after close. The two broken-title families were addressed with closing conditions: the target had to obtain and record a confirmatory assignment from the departed engineer and record the intra-group transfer before completion, with the leverage still on the buyer’s side while the inventor remained reachable. What could not be cured pre-close was priced — roughly 15% of the IP-attributed consideration moved into an escrow and a specific indemnity tied to the title and encumbrance risks.

The valuation range was rebuilt on what the target could actually convey. The exclusive license-out was carved out of the exclusivity assumption, the lapsed families were struck from the asset base, and the defensible number the fund underwrote was lower than the one the seller had presented — but it was a number the investment committee could interrogate line by line. The red-flag register graded each finding as a price adjustment, an indemnity, a condition to closing or a reason to walk, so the deal team could see exactly which lever each one moved.

The deal still closed — but on terms that reflected what was really being bought. The buyer avoided paying an exclusivity premium for a non-exclusive asset and inheriting a title defect that would have surfaced, far more expensively, in a post-close dispute. The diligence paid for itself several times over in the single line of the purchase price it moved.

Sequencing was what made the cure possible. Because the title work ran during confirmatory diligence rather than after signing, the departed engineer’s confirmatory assignment could be negotiated while the buyer still held leverage and the seller still had reason to cooperate. Had the same gap surfaced a year after close, the company would have been negotiating from weakness against a former employee under no obligation to help — the difference between a closing checklist item and a lawsuit. The timing of the review, not just its findings, is part of what protected the price.

What This Means for Similar Matters

The lesson that generalises is that in an IP-driven acquisition, the balance sheet audits the wrong assets. The value is in the patents, marks and trade secrets, and their condition — owned outright, licensed out, jointly held, encumbered or merely asserted — is invisible in the financials and decisive to the price. A review that stops at audited accounts is auditing the minority of the value.

The second lesson is that chain of title is the cheapest defect to fix before signing and the most expensive to discover after. A missing assignment found while the inventor is still cooperative and the buyer still holds the leverage is a closing condition; the same defect found after the wire clears is litigation. Verifying ownership against the recorded USPTO record — not the data-room schedule — is what keeps a paperwork lapse from becoming a purchase-price dispute.

The third lesson is about what a ‘proprietary’ label actually means. A target will describe its technology as exclusive because, in its own experience, no competitor is using it — but exclusivity is a legal fact recorded in licences and assignments, not a commercial impression. The exclusive license-out here was disclosed in the data room; it simply was not framed as the constraint it was. Diligence earns its fee precisely at that gap between how a seller honestly describes its IP and what the enforceable documents say, and closing that gap before the price is fixed is the whole point of the exercise.

Taken together, this M&A IP due diligence case study makes a single point that travels to any IP-driven deal: what a target can prove it owns — against the recorded register, not the data-room narrative — is what a buyer is actually paying for. Everything the review produced, from the chain-of-title findings to the rebuilt valuation range, existed to close the distance between those two things before the number was fixed. That is the discipline an M&A IP due diligence case study is meant to demonstrate, and the reason the work belongs on the critical path of the deal rather than in a file reviewed after it has already closed.

Data Sources

The market and patent data referenced above comes from:

• EPO–IEA study: Innovation in batteries and electricity storage — Joint EPO/IEA analysis: batteries account for ~9 in 10 electricity-storage patents and storage patenting grew ~14% a year (2005–18), four times the all-field average.
• EPO Patent Index 2024 — European filing data recording battery-technology filings up 24.0% year on year and electrical machinery/energy up 8.9%.
• 35 U.S.C. § 261 — Ownership; assignment — The statute making an unrecorded patent assignment void against a later good-faith purchaser unless recorded within three months of execution.
• USPTO Patent Assignment Search — The public recorded-assignment database used to verify a target's chain of title against its own schedule.

Discuss a Similar Matter

If you are underwriting an IP-heavy acquisition, we can rebuild the target’s portfolio from the primary record, verify chain of title and price the risk before you sign.

Related PerspireIP work: M&A IP Due Diligence · Semiconductor Patent Landscape · IP Valuation.

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