Prantik Mazumdar and his business partner Rachit Dayal built Happy Marketer, a digital marketing agency, to more than $10 million in annual revenue before they decided to sell to Dentsu Aegis Network. Mazumdar and Dayal agreed to sell for around 7 times EBITDA, 40% of which was paid up front with the remainder available in a four-year earn-out tied to the future profitability of Happy Marketer.