NYSE Euronext is in talks to sell itself to rival IntercontinentalExchange Inc. for about $8 billion, in a deal that would end more than two centuries of independence for the New York Stock Exchange, one of Wall Street's most enduring symbols of American capitalism.

Late Wednesday, the two companies were discussing a cash-and-stock transaction that would value NYSE at about $33 a share, people close to the talks said. The agreement could involve ICE buying NYSE Euronext and then selling its counterpart's stock-exchange businesses in France, the Netherlands, Belgium and Portugal, one of the people said.

An announcement could come as early as Thursday, the people said. A NYSE spokesman said Wednesday night that the company doesn't comment on rumors. An ICE spokeswoman declined to comment.

Exchanges have turned in recent years to mergers to help offset intense competition and the relentless decline in trading commissions they pocket from brokers and other market participants. Yet the deal-making appeared to reach its limit last year, when several large cross-border mergers failed amid regulators' concerns.

The discussions come about a year and a half after ICE last tried to acquire at least a piece of NYSE Euronext. ICE and Nasdaq OMX Group Inc. had proposed in April 2011 to buy NYSE Euronext for about $11 billion. As part of the offer, Atlanta-based ICE had looked to buy NYSE Euronext's derivatives businesses, while Nasdaq would have taken control of the stock exchanges.