Robo-adviser Moneybox posted a loss of £3.1m for the 12 months to the end of May.
Moneybox launched in 2015 and allows people to start saving by rounding up their purchases to the nearest pound and investing this spare change.
In the year to the end of May 2018, its losses nearly doubled from £1.8m in the previous year to £3.1m.
This was despite revenue increasing by 1,092 per cent, from £46,665 to £556,393.
The company's co-founder, Ben Stanway, said Moneybox was investing to grow the business, specifically by increasing the number of employees across all departments.
The company's expenses more than doubled from £213,418 to £472,832 in the 12 months to the end of May.
Moneybox plans to launch a pension in the first quarter of next year, which will incorporate additional planning tools.
The company added 70,000 new clients in 2017 - its first full year.