Toronto-Dominion Bank is buying regional bank First Horizon in a $13.4 billion all-cash deal, its biggest ever, hoping to broaden its footprint in the southeastern U.S.

The deal would create one of the top six banks in the U.S., the companies said Monday, with approximately $614 billion in assets and a network of 1,560 locations serving over 10.7 million U.S. customers across 22 states.

TD Bank Group will pay $25 for each share of First Horizon Corp.

"The Southeastern U.S. represents a tremendous opportunity for TD and the addition of First Horizon's commercial and specialty banking capabilities will position us as a leading national player in commercial banking," said TD CEO Leo Salom.

In addition to its home state of Tennessee, First Horizon operates in Louisiana, Florida, North Carolina, South Carolina and Virginia. It also has important footholds in major southern urban centers like Atlanta, Dallas and Houston.

TD, based in Toronto, said it is committed to maintaining First Horizon's banking locations with no planned branch closures.

TD anticipates $1.3 billion in merger and integration costs, mostly in the first two years after the transaction closes. It expects about $610 million in cost savings.

The deal is targeted to close in the first quarter of TD's 2023 fiscal year. It still needs approvals from First Horizon's shareholders and U.S. and Canadian regulatory authorities. The transaction will end, unless otherwise extended, if it does not close by Feb. 27, 2023.

Shares of First Horizon soared more than 30% Monday.