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Dying · US7440920
Tool for estimating a cost of a trade
The patent that outlived its bank. Lehman Brothers filed this in August 2006 — two years before it collapsed into the largest bankruptcy in US history. The patent kept its term running through the collapse, the liquidation, and eighteen years afterward.
Assignee: Lehman Brothers Inc. · Filed 2006-08-01 · Granted 2008-10-21 · Est. expiry 2026-08-01
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Dates here are estimates from patent-term math (20 years from filing, or the older 17-from-grant/20-from-filing rule for pre-1995 filings), not a legal determination. They ignore patent-term adjustments, extensions, and terminal disclaimers, and don't reflect maintenance-fee lapses that haven't happened yet. 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 — it gets sold, assigned, or simply sits on a balance sheet in liquidation. Lehman the bank has been gone for eighteen years. Lehman's patent, filed by traders who had no idea what was coming, keeps its full twenty-year term regardless.
On August 1, 2026 — exactly twenty years after filing — the term runs out and a trade-cost estimation method becomes free to implement, for a bank that no longer exists, in a market structure that has moved on twice over since.
Patent record: US7440920