U.S. Bancorp has completed its $8 billion acquisition of MUFG Union Bank's core retail banking operations, the bank said Thursday.

The deal will give the Minneapolis-based bank a much bigger presence in California, Oregon and Washington, where MUFG has about 300 branches.

Executives have said it will also help the bank, the fifth-largest in the U.S., be more competitive and invest more in technology and digital services.

"The acquisition of MUFG Union Bank underscores U.S. Bank's commitment to creating economic opportunities for our customers and communities across the West Coast," Andy Cecere, U.S. Bancorp's CEO, said in a statement.

This is the second-largest deal for a Minnesota-based company this year after UnitedHealth Group's $13 billion purchase of Change Healthcare.

And it's the largest transaction for U.S. Bancorp since its $21 billion merger with Milwaukee-based Firstar Corp. in 2001.

The merger was first announced in September 2021. Bank leaders initially hoped to close the deal in the first half of this year.

But it took longer than anticipated to get federal regulatory approvals amid leadership changes and additional scrutiny of regional banks' ability to weather economic downturns.

Those regulatory approvals finally came through in mid-October.

MUFG Union Bank is the the main segment of the U.S. operations of Japan's largest bank, Mitsubishi UFJ Financial Group.

Account conversions and systems integration is expected to take place in the first half of 2023. U.S. Bank said it will provide more information to MUFG customers in coming weeks.