In 2021, when Roshan Patel was raising his startup Walnut’s first round of funding, his email inbox overflowed with interest from investors. Venture capitalists loved his idea of applying the fast-rising concept of buy-now, pay-later, a $100 billion industry, to health care bills. Patel secured $3.6 million that spring and kept in touch with a few investors who might chip in more as the company grew. READ MORE