Fidelity Investments, the second-biggest U.S. mutual-fund company, named Abigail P. Johnson chief executive officer, succeeding her father Edward C. “Ned” Johnson III to become the most powerful woman in the fund industry.

“Abby will retain her role of President,” Ned Johnson, 84, said in a letter to internal shareholders, adding that he will stay on as chairman of the board.

Fidelity signaled that Johnson, 52, was the clear successor to her father in 2012 when it named her president overseeing asset management, retail and institutional brokerage, retirement and benefits services. The appointment resolved the long-running question of succession at the family-controlled firm run by her father for more than three decades.

The younger Johnson, who started her career at Fidelity in 1988 as a mutual-fund manager, has worked in almost every major division at the company. She was named head of the firm’s mutual-fund unit in 2001 and put in charge of Fidelity’s retirement business in 2005. In 2007, the company also gave her oversight of corporate-retirement services and fund sales to individuals.

Abigail Johnson has a net worth of $9.2 billion, according to the Bloomberg Billionaires Index.