Westpac has lost its High Court appeal over a campaign to get customers to switch to the bank's BT Super account.
The bank was previously found by the Federal Court to have breached financial services laws and not acted in customers' best interests over the campaign.
Westpac sought to overturn the finding, but lost in the High Court on Wednesday.
Appeal judges maintained the bank breached the Corporations Act by providing personal advice in calls to 14 customers. It was part of a campaign to get existing customers to move their super from external funds to BT.
This netted Westpac nearly $650 million between January 2013 and September 2016 before financial regulator ASIC took legal action.
"Westpac were actively conducting a sales campaign aimed at rolling customers into Westpac products under the banner of general advice," Commissioner Danielle Press said in a statement.
Westpac acknowledged the court decision, and said it provided "important guidance on the distinction between general and personal advice".
