The New York Stock Exchange has announced plans to merge with an electronic stock trading company called Archipelago.

The NYSE is the world's biggest stock exchange and is the last major exchange where stocks are bought and sold by traders shouting and gesturing at each other.

Exchange chief John Thain says the two-century-old tradition of "open outcry" trading will continue on the NYSE alongside the electronic trading system, where buyers and sellers are matched by computer.

But some analysts say the old system is not likely to survive for long.

The NYSE will also change from a non-profit entity to a regular company.

The changes will have to get approval from regulators.