NEW YORK, March 19 (Reuters) - Nasdaq said on

Tuesday that Borse Dubai will sell shares worth $1.6 billion in

the U.S. stock exchange operator, reducing its stake to 10.8%

from 15.5% and making it the company's second-largest

shareholder.

Borse Dubai, currently Nasdaq's top shareholder, will sell

nearly 27 million Nasdaq shares at $59 each, a discount of more

than 5% to the stock's closing price on Tuesday.

Nasdaq's shares closed the regular session up 3.6% at

$62.46. They fell more than 2% in extended trading on Tuesday

following the announcement of the planned share sale.

"Subject to completion of the offering, Borse Dubai intends

to agree to an 18-month lock-up of its remaining shares

controlled by Nasdaq, with a right to designate a nominee to the

Nasdaq board of directors so long as it continues to own at

least 10% of Nasdaq's outstanding shares as of the date hereof,"

the company said in a statement.

U.S. private equity firm Thoma Bravo will become Nasdaq's

largest shareholder, holding a 12.5% stake in the U.S. exchange

with about 71.6 million shares.