^Francis, Don. George Zachary Calls Pebble His Best Investment To Date. Startup Grind. February 4, 2014. When asked by StartupGrind founder and interviewer, Derek Andersen, about the investment, George called said Pebble has not only been the fastest growing investment based on revenue, but also the most profitable. Charles River Ventures invested $15 million Series A funding in 2013. George confirmed that Pebble had shipped 300,000 units in its first year of operation.