Toronto-Dominion Bank’s handling of suspicious customer transactions was the reason regulators wouldn’t approve the Canadian company’s $13.4 billion purchase of First Horizon Corp., the Wall Street Journal reported, citing people familiar with the matter.

The regulators’ concerns were related to the way the Toronto-based bank handled unusual transactions in recent years and whether they were brought to the attention of US authorities quickly enough, the people told the newspaper. Reluctance by the Office of the Comptroller of the Currency and the Federal Reserve to sign off on Toronto-Dominion’s anti-money-laundering practices ended up being the biggest obstacle, the Journal said, citing the people.

Representatives for Toronto-Dominion and the OCC didn’t immediately respond to requests for comment from Bloomberg News. The Fed declined to comment. The bank “works diligently to prevent criminals from using the bank for illegal activity, to strengthen its risk-management programs on an ongoing basis and to protect the interests of our customers, the bank and the financial system,” a spokeswoman told the Journal in an emailed statement.

Canada’s second-largest lender walked away from the deal for Memphis-based First Horizon last week, saying it’s uncertain whether it can get regulatory approval. It would have been Toronto-Dominion’s largest acquisition ever, adding more than 400 branches in the US Southeast to fill in a network that already stretches down most of the eastern seaboard.

--With assistance from Derek Decloet and Katanga Johnson.