Y Combinator backed Indian Fintech Karbon Secures $12M in Pre-Series A from Unicorn Ramp, Rainfall Ventures, Roka Works  Crowdfund Insider. : Karbon Card, a Fintech firm providing corporate cards, has secured $12 million (appr. INR 88.8 crore) in a Pre-Series A funding round from US-based Fintech Unicorn Ramp, Rainfall Ventures, Roka Works, Y Combinator, and other international investors. Ramp is a New York-headquartered spend/budget management app or corporate charge card start-up that became a Unicorn with a valuation of $3.9 billion in just a couple of years.