SCOTT JAGOW: Companies merge or form alliances all the time, so why can't stock exchanges? The Wall Street Journal says the New York Stock Exchange and the Tokyo Stock Exchange might do a deal. The NYSE's already got a deal with a European exchange. Ashley Milne-Tyte has more.

ASHLEY MILNE-TYTE: If a deal with the Tokyo exchange went through, traders in New York would have access to round-the-clock markets in the U.S., Europe and Asia.

James Cox teaches corporate and securities law at Duke University. He says if the NYSE owned a stake in the Tokyo exchange the main beneficiaries would be the money managers for pension funds and other institutional investors.

JAMES COX:"The sophisticated market traders who now when the sun sets on the New York Stock Exchange has to engage in after-hours trading where greater transaction costs arise . . ."

He says as for Tokyo, a deal with the NYSE would give the city a major leg-up over markets in Hong Kong and Shanghai.

And because the Tokyo exchange is a private company, Cox says, the deal could be easier to pull off than one involving a public company with responsibility to shareholders.

In New York, I'm Ashley Milne-Tyte for Marketplace.