The startup, which only officially opened its doors in March, has already passed $90 million in deposits, with an average account balance of nearly $30,000.

Rather than reward those with the biggest balances or those that make the most transactions, HMBradley's model lets customers earn more interest the more they save.

The firm has four savings tiers, ranging from a 0.5% APY for customers that save between five per cent and 10% of their income, to a three per cent APY for those saving more than 20%.

In July, it introduced a credit card, offering consumers three per cent cash back for purchases in their highest spending category, two per cent for the next highest category, and one per cent for all additional charges, automatically adapting each cycle to how customers spend their money.

The funding will be used to ramp up the credit programme and to make hires. Among the recent additions to the team are former director of engineering at Capital One, Ben Coffman.

Zach Bruhnke, CEO, HMBradley, says: "We started HMBradley with the thesis that people of all income brackets want to save money, but they sometimes need a little help or incentive to do that.

"Every day since our launch, our account holders have proved this to be true. HMBradley’s 3% APY is not a gimmick. We stand behind it because it serves as strong encouragement for customers to practice the financial behaviors that set them up for success."

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