Jim McCool (right), Charles Schwab's executive vice president of institutional business, made waves at an asset-management conference in March when he announced that the brokerage firm soon would offer 401(k) retirement plans stuffed solely with exchange-traded funds. The Wall Street Journal reports he added that the San Francisco-based investment giant would let investors trade them without charge.

"You could tell the rest of the room was nervous about it," Mike Alfred, co-founder and chief executive of BrightScope Inc., told the paper. "The idea is disruptive."

The Journalnotes Schwab is a bit player in 401(k)s, but sees ETFs as a way to edge closer to giants such as Fidelity Investments, Aon Corp.'s Aon Hewitt and Vanguard Group. According to consulting firm Cerulli Associates, those three had a combined market share of about 43% in 2009, the latest year for which data are available.