Smartleaf Inc., a provider of overlay portfolio management solutions to banks and financial services companies, announced Monday that U.S. Bancorp has chosen it to provide a unified overlay platform for its non-brokerage wealth management investment relationships managed through the private client reserve and private client group.

Smartleaf, which in based in Cambridge, Mass., has provided overlay solutions for U.S. Bank’s non-brokerage unified managed account program since 2007.

Smartleaf will now manage over 40,000 client portfolios for U.S. Bancorp, which is the fifth largest U.S. banking company.

Tim Leach, the chief investment officer for U.S. Bank’s wealth management group, said in a press release that the Minneapolis company selected Smartleaf because of the success it has had with the bank’s UMA progress. He said the banking company was “impressed by [Smartleaf’s] ability to simultaneously provide client investment preference customization, a high degree of tax efficiency, consistency, and the ability to view and respond to each account’s needs daily.”

With the expanded use of the Smartleaf system, U.S. Bank will manage portfolios that combine individual equities, individual fixed income securities, mutual funds, ETFs, structured notes and other securities in a single portfolio that benefits from both proprietary and third-party research/models.

Jerry Michael, the president of Smartleaf, said in a interview Thursday that as a result of this new agreement U.S Bank will be Smartleaf’s largest customer.

Smartleaf has $35 billion in assets under management, up from $15 billion a year earlier. He said U.S Bank will continue to offer proprietary investment products, but these products can be assimilated into a UMA.

“Overlay isn’t just for open architecture anymore,” he said. “We see overlay as being adopted as a common platform to manage wealth.”

Smartleaf, which was founded in 1999, has relationships with 50 firms. Michael said the company had decided from its inception to focus on the bank channel, but has developed relationships in other channels as well.

Michael said Smartleaf plans to continue to expand by adding more banks. He said the pipeline is “strong” and he expects to add more relationships this year.

“We are very pleased with our growth in the past year,” he said. “We are not projecting a specific growth target, but we like this trend that overlay is being adopted as the common platform."