Activist investor Nelson Peltz has upped his stake in the Bank of New York Mellon Corp., the world’s largest custody bank, to 2.5 percent, reported The New York Times.

Trian Fund Management LP, a hedge fund cofounded by Peltz, announced in a statement that it has contacted Mellon with the aim of discussing “ideas and initiatives to drive long-term growth and enhance shareholder value,” Bloomberg News reported.

“Trian is a respected investment firm,” said Kevin Heine, a spokesman for Bank of New York Mellon, The New York Times reported. “We look forward to engaging with them as we do all our investors.”

In a March 31 filing with the Securities and Exchange Commission, Trian revealed that it had a 0.8 percent stake in the bank. Trian requested that the SEC keep its stake in Mellon confidential, but that privacy request expired today, according to the filing.

Since its March filing, Trian has continued to purchase shares in the bank, and now owns 28.9 billion shares, collectively worth $1.05 billion, Trian spokesperson Andrea Calise told the New York Times.

With low interest rates reducing their income, custody banks like Mellon have been under pressure to cut expenses, said Bloomberg News. “Mr. Peltz’s Trian has a history of buying shares in companies and then pressing management to improve performance,” The New York Times wrote.