The New York Stock Exchange called time on two centuries of independence on Thursday, agreeing to an $8.2bn takeover that will hand control of the icon of American capitalism to an Atlanta-based energy trader.

The stock exchange's holding company, NYSE Euronext, has agreed to an offer of $33.12 a share in cash and stock from IntercontinentalExchange (ICE). ICE was founded in 2000, NYSE in 1817. The combined company would have headquarters in both ICE's home of Atlanta and in New York.

The takeover comes amid a historic shift for Wall Street and stock exchanges around the world. The move to electronic trading, fierce competition between exchanges and the sharp decline in trading commissions has led to a wave of mergers and takeover offers that have failed amid regulatory concerns.

The exchange, also called the Big Board, has moved to embrace technology in recent years but still also uses the "open outcry" system with traders in bright-coloured jackets shouting and waving their hands to make orders.

Charles Geisst, author of Wall Street: A History and a finance professor at Manhattan College, said: "The NYSE has faded in the past few years, for most professionals this is a sign of the times. Trading could take place on the moon right now as long as you have the right communications."

Jack Ablin, chief investment officer at BMO Private Bank, said: "The NYSE is an icon but it runs the risk of becoming irrelevant, it's just being outplayed by its more technologically savvy competitors."

"When I started out NYSE was the stock market," said Ablin. "But things are changing at an exponential speed. It's become less and less relevant with every passing year."

Last year ICE teamed up to make a bid for NYSE with Nasdaq, the New York-based exchange that is home to tech giants including Apple and Facebook. That deal fell apart amid regulatory concerns. The US bid followed an attempt to merge with Germany's Deutsche Borse, which triggered concern with European regulators and a protectionist backlash in Washington. NYSE Euronext's shares have fallen over 30% since the ICE and Nasdaq bid failed and ICE's latest offer is $3bn less than the previous one.

"The Board of NYSE Euronext carefully considered a range of strategic alternatives and concluded that ICE is the ideal partner for NYSE Euronext in an evolving market landscape," said Jan-Michiel Hessels, the chairman of NYSE Euronext's board.

The NYSE once dominated stock trading in the US but has been losing market share since the 1990s when the all-electronic Nasdaq opened for business and new rules allowed shares to be traded more freely across multiple venues. Today Chicago's CME is the predominant exchange in the US, valued at $17.5bn, $10bn more than NYSE Euronext.

"There was a time when NYSE was 60-70% of the equities traded in the states. Now on a good day it's about 20%," said Geisst.

The exchange moved to embrace the change in 2005 by buying electronic-trading company Archipelago and becoming a public company. In 2006 it merged with Euronext, which operates stock-exchange businesses in France, the Netherlands, Belgium and Portugal.

ICE was founded in 2000 by chairman and chief executive officer Jeffrey Sprecher as an electronic commodity trading exchange. Sprecher has grown the business through a series of big deals. ICE now runs the world's biggest energy futures market and commodity markets in the US and Canada. The deal will add NYSE Liffe, the European derivatives exchange to ICE's portfolio, a business Sprecher has long coveted.

"Our transaction is responsive to the evolution of market infrastructure today and offers a range of growth opportunities, while enhancing competition in US and European markets and broadening our ability to address new markets and offer innovative products and services on a global platform," said Sprecher.