Martin Lewis is urging people to claim £170 for free before the offer runs out in just five days time.
The cash is offered as an incentive for bank customers to switch to HSBC's Advance current account from another banking provider. Anyone wanting to claim the cash must do so by July 18.
And it's not available to everyone. In order to be eligible for the switch reward, you can't have had an HSBC current account, or opened one with its sister bank First Direct, since January 2019, to claim the cash.