Zennstrom lives in England but is sailing under the Swedish flag. He won race 3 and placed second in race 4 Tuesday. The 10-race series concludes Friday.
Hedgehog is captained by Bermuda's Alec Cutler with Canadian Olympic sailing medalist Richard Clarke as tactician.
It continues to lead the 23-boat Melges 24 class and is four points ahead of Full Throttle, skippered by Brian Porter of Lake Geneva, Wis.
Barking Mad has Bostonian James Richardson at the helm with tactician Terry Hutchinson. It moved to the top of the leaderboard in the Farr 40 class.
The event has attracted 121 sailing teams divided into 11 classes.