Tax Farming
The societates publicanorum were large private companies contracted by the Roman state to collect taxes and carry out public works. The censors put provincial tax rights out to competitive tender, customarily on five-year contracts, and companies formed by the equestrian class won them. Cicero records that such tenders could be accepted only in the presence of the Roman people. When more capital was needed, the answer was not to sell shares but to form a sub-partnership beneath the contract. Half the story of the «ancestor of the joint-stock company» turned out to be myth — but the shape itself, pooling capital to take on a contract with the state, does genuinely anticipate the chartered companies sixteen centuries later.
The myth, corrected
Rome had a stock market
The received view that shares (partes) were actively traded was strongly contested by Poitras and Geranio in 2016 (Explorations in Economic History). The trading floor said to have stood near the Temple of Castor is a later romanticisation, and the equestrian class eligible to bid numbered only some seven hundred and thirty men. Not one dispute over the trading of shares survives in Rome's enormous body of legal material. The belief was «discovered» in the nineteenth century by philologists reading a modern stock market into a sentence of Cicero.