Glitches at robo-advisor sites caused complaints this week, causing some to question this niche in the financial industry.

Corporate pension funds like bonds as a way of minimizing volatility, but companies might not have to issue as many bonds under the tax bill.

None other than Vanguard founder Jack Bogle is raising the prospect that too much money is in too few hands, with BlackRock, Vanguard and State Street Corp. together owning significant stakes in the biggest U.S. companies.