And their computers probably ran DOS in the beginning

I was curious about the age of the New York Stock Exchange (NYSE).

According to several sources, it's pretty old.

eNotes states that the exchange started on "May 17, 1792, when local brokers met under a designated tree to buy and sell securities." Don't know what they did when it rained or snowed.

eNotes states that the...um, "modern" version of the exchange began on Wall Street in 1825. However, nndb lists the founding date as 1817.

The NYSE's own website uses the 1792 date.

Twenty-four prominent brokers and merchants gather on Wall Street to sign the Buttonwood Agreement, agreeing to trade securities on a commission basis. The New York Stock Exchange traces its beginnings to this historic pact.

The NYSE website states that the organization moved to 40 Wall Street in 1817, and established a constitution at that time.

As for 1825:

1825
Erie Canal Opens

The opening of the Erie Canal makes New York City the seaboard gateway for the Great Lakes region. New York State bonds, issued to finance the canal, are traded actively on the Exchange.

Presumably investors refrained from stating that their investments were "underwater."