The resurrected
Five expired trading patents, rebuilt as playable, interactive demos. Nothing here needs a license — the mechanisms these patents once protected are public domain. Play with the actual invention.
Wagner Matching Engine
An automated futures-matching exchange, filed in November 1983 — one of the earliest attempts to put a human trading pit inside a computer.
News-Sentiment Trading Signal Backtester
Filed in 2002, before 'NLP' meant much more than keyword rules and bag-of-words models. Its owner let it lapse for unpaid fees around 2024 — years before its adjusted term would have ended, and right as LLMs made news-sentiment trading mainstream.
Virtual Specialist AMM
A software 'specialist' that always quotes a two-sided market and takes the other side of every trade — the automated-market-maker idea, patented in 1996, years before AMMs became the backbone of on-chain trading.
Financial Advisory System (1997)
Financial Engines — co-founded by Nobel laureate William Sharpe — patented automated portfolio advice in 1997, a full decade and a half before 'robo-advisor' became a marketing category.
Linked Global Exchange
A satellite-linked scheme for trading commodities across time zones and exchanges as one continuous market — filed in 1984, when a 24-hour global market was still a proposal, not a fact of life.
Frequently asked questions
Can I use an expired or public-domain patent?
Once a patent's term ends or it lapses for non-payment, the invention it claimed generally enters the public domain and can be made, used, or sold without a license from the former owner. Separate copyrights, trademarks, or other patents may still apply to a specific product. This is general information, not legal advice.
Is an estimated date the same as a legal ruling?
No. Dates here are computed from public filing data and can differ from a patent's real status in either direction. Confirm against USPTO records before relying on one.
What does a maintenance-fee lapse mean?
US patents require maintenance fees at 3.5, 7.5, and 11.5 years after grant. If the owner stops paying, the patent lapses early and the invention enters the public domain years before its term would otherwise end.