Total processing volume (TPV) measures the amount of money people spend through Marqeta's platform, net of returns and chargebacks. Although I think the company has the potential for rapid growth, the stock is best suited for investors with a long time horizon and a high-risk tolerance who are willing to hold this fintech, which could struggle as the economy likely slows into next year. Inflation and rising interest rates have weighed on stocks this year, with the S&P 500 index down over 20% in the year's first half.