Twitter shares have been priced at $26 each, ahead of its debut on the New York Stock Exchange (NYSE) later.
That is above the $23 to $25 range announced on Monday and values the short messaging service at more than $18billion (£11bn).
That makes it the biggest market debut for a technology firm since Facebook went public in May 2012.
Twitter has attracted 230 million users since starting seven years ago, but is yet to make a profit.
