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Dying · US7440920
Tool for estimating a cost of a trade
The patent that outlived its bank — but not by as long as we first wrote. Lehman Brothers filed it in August 2006, two years before collapsing into the largest bankruptcy in US history. It granted five weeks after the Chapter 11 filing, passed to Barclays with Lehman's US business, and ran until 2021.
Correction (July 12, 2026): this page originally counted this patent down to August 1, 2026. Verified against USPTO data, its term was anchored to an earlier parent application, not its own 2006 filing date — the listed expiration is April 14, 2021. It has been dead for five years. Google Patents lists its status as Expired — Lifetime.
Assignee: Lehman Brothers Inc. (assigned to Barclays Capital, October 2008) · Filed 2006-08-01 · Granted 2008-10-21 · Adjusted expiry 2021-04-14
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Dates on the curated countdown pages are USPTO-adjusted expiration dates (verified against USPTO/Google Patents legal-status data as of July 2026, including patent-term adjustment); they still assume maintenance fees keep being paid, and are not a legal determination. Dates in the searchable database are raw patent-term math (20 years from filing, or the older 17-from-grant rule) that ignores adjustments, extensions, and terminal disclaimers. This is not legal advice.
Lehman Brothers filed US7440920 — a tool for estimating the cost of executing a trade, the kind of transaction-cost-analysis logic every institutional desk runs before a large order — on August 1, 2006. It granted October 21, 2008, five weeks after Lehman filed for Chapter 11 on September 15, 2008.
Patents don't die with their assignee. They're property, and property survives bankruptcy — this one was assigned to Barclays Capital in October 2008, along with the rest of Lehman's North American business, before the ink on its own grant was dry. The traders who filed it had no idea the name on the assignment line would change before the patent existed.
It also didn't get the full twenty years we originally credited it with. Its term was tied back to an earlier parent application, and the USPTO-listed expiration came on April 14, 2021. The trade-cost estimation method it claimed has been free to implement since then — for a bank that no longer exists, in a market structure that has moved on twice over.
Patent record: US7440920
Sources & further reading
Frequently asked questions
What happens on the countdown date?
That date is the patent's USPTO-adjusted expiration — verified individually against USPTO legal-status data (patent-term adjustment included) in July 2026. When it passes, the patent's term has ended and the claimed invention enters the public domain. It's still an estimate of status, not a legal ruling.
Is the countdown date guaranteed?
It's much stronger than raw patent-term math — each date on the countdown list was checked against USPTO-adjusted expiration data — but it still assumes maintenance fees keep being paid (a lapse would only make the death earlier), and it isn't a legal determination. Confirm against USPTO records before relying on it.
Can I build the invention once it expires?
Once the term ends, the specific claimed invention generally becomes free to make, use, or sell without a license. Other patents or rights may still cover a particular product; this isn't legal advice.