Management consulting firms Towers Perrin and Watson Wyatt said Monday they have completed their merger, creating a firm with 14,000 employees in about two dozen countries.
The combined company's shares began trading on both the New York Stock Exchange and the Nasdaq under the symbol "TW" on Monday. The stock was up $2.24, or 4.7 percent, to $49.76 in afternoon trading.
The companies cleared regulatory hurtles and a shareholder vote last month after announcing in June that they would form one company under the name Towers Watson & Co.
They combined in an all-stock deal that valued the two at roughly $4 billion based on the closing share price of Watson Wyatt's stock last week.
Watson Wyatt CEO John Haley will assume the top job at the combined company, with Towers Perrin CEO Mark Mactas serving as chief operating officer.