Wall Street's stock pickers just got a lifeline

Passive investing is shaking up the money-management world.
Exchange-traded funds, which simply track an index, have hoovered up assets over the past decade.
The funds, which are low cost, tax efficient, and offer liquidity and transparency, pose an existential threat to the actively-managed funds industry.
Actively managed funds, which are run by stock pickers and bond managers, charge higher fees and have struggled for performance of late.
Now those active managers have a chance to fight back