According to a new filing with the US Securities and Exchange Commission on Friday, Stash Financial Inc., a popular investment app that opened access to cryptocurrencies earlier this month, has raised $52.6 million in a debt offering. According to the filing, the offering began on September 6. The $52.6 million was the total Stash planned to raise in this offering, and the capital came from a dozen investors. According to Sarah Spagnolo, Stash communications vice president, the offering consists of convertible debt from a mix of new and existing investors. Convertible debt is a type of debt instrument that can be converted into equity or shares of the issuing company.