NYSE Euronext agreed to sell itself to rival IntercontinentalExchange Inc. for about $8.2bn, 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.

The two companies said Thursday they agreed to a cash-and-stock transaction that values NYSE at $33.12 a share. Investors can opt for all cash, or 0.2581 IntercontinentalExchange common shares for each NYSE Euronext share or a mix of $11.27 in cash plus 0.1703 Ice shares.