Fidelity has filed the latest salvo in the brokerage industry's price war by offering its RIA clients commission-free online trades on 25 iShare ETFs and the Fidelity Nasdaq Composite Index Tracking Fund.

The company is also lowering and simplifying its online commissions on other U.S. equity trades-going to a flat commission of $7.95 per trade in place of a more complicated fee schedule tied to client assets and trade volume.

Fidelity's previous fee schedule was $17.95 or greater for households with less than $1 million in assets under custody at the company.

Fidelity's decision, in partnership with Black Rock's iShares unit, to waive commissions on 25 iShares' ETFs comes only two months after Schwab introduced eight of its own proprietary ETFs. The move further intensifies competition in the fast-growing ETF space and the race for ETF assets is unlikely to abate any time soon.

Fidelity's asset management arm, which usually positions itself on the cutting edge of emerging trends in financial services, has introduced only one ETF to date. While the Boston-based giant clearly is worried about cannibalizing its sprawling mutual fund business, industry observers expect the firm to roll out a group of ETFs with a big splash later this year.