The NYSE dates to 1792, when 24 brokers and merchants traded stocks under a buttonwood tree on Wall Street.
But today most trading doesn't require face-to-face meeting at all. It's done on computers that match thousands of orders a second.
The introduction of negotiated, rather than fixed, commissions for securities transactions, in May 1975, marked the start of a gradual decline in brokerage fees for traditional stock trading.
It also gave rise to so-called discount brokerages, like Charles Schwab, that offered to trade for customers at lower rates.
"The cash equities business in America has effectively been obliterated," said Thomas Caldwell, chairman of Caldwell Securities in Toronto and a shareholder in the New York exchange's parent company, NYSE Euronext.
He said that the jewel of the deal is not the New York exchange but Liffe, a futures exchange founded in London, further underlining the growing importance of the futures markets.
While brokerage fees have declined, futures exchanges have retained profit margins, said James Angel, an associate professor in finance and an expert on stock exchanges at Georgetown University's McDonough School of Business.
Stock trading is a "dog-eat-dog business where the profit margin per share is measured not in pennies, not in tenths of pennies, but in hundredths of pennies", said Angel, who also sits on the board of Direct Edge, a smaller stock exchange.
Last year, ICE and Nasdaq OMX Group, which competes with the NYSE for stock listings, made an US$11 billion bid to buy NYSE Euronext. But that deal fell apart after regulators raised antitrust concerns.
Deutsche Boerse, a German company, made a bid for NYSE Euronext, but that was scuttled by European regulators.
ICE was established in May 2000. Its founding shareholders represented some of the world's largest energy companies and financial institutions.
The deal has been approved by the boards of both companies, but still needs the approvals by regulators and shareholders of both companies. It is expected to close in the second half of next year.
- AP