Two years ago Eaton Vance, the $336 billion Boston-based active manager, entered new territory by becoming the first active manager to receive SEC approval for a new breed of exchange-traded funds.

Branded as NextShares, the funds - the first of which were launched in the US in February - enable an active fund to exist inside an ETF without having adhere to the daily transparency required of traditional ETFs, meaning managers avoid giving away their investment IP.