The back-office securities servicing arm of Bank of New York Mellon says it has topped the $100 billion mark in exchange-traded fund assets. At that level, BNY Mellon Asset Servicing claims to be the largest U.S. custodian for ETFs in terms of funds serviced.

In a statement released Tuesday morning, the firm says that it now provides services to more than 350 separate funds. BNY Mellon's ETF services business has grown from a single portfolio with less than $1 billion in assets in the past decade, according to Joseph Keenan, managing director of BNY Mellon Asset Servicing.

He credited the group's climb to the top at least in part to the market's recent upswing. Longer term, Keenan noted the explosive growth in ETF popularity over the past several years. ETF services include custody, accounting and administration as well as transfer agency servicing.

"We will continue to invest in all aspects of this business from technology to client service so we can meet the growing needs of investment managers and contribute to the continuing success of our clients," said Keenan in a statement.