The Fidelity Investments and BlackRock expanded partnership made waves in the exchange traded fund business, but it may also influence the retirement account market as well.

The new deal could push more employers to work with Fidelity in including a self-directed brokerage option within their plans, reports Nicole Seghetti for The Motley Fool. [ETFs and Retirement Accounts]

“To the extent that iShares will be more readily available without transaction fees in those accounts through Fidelity, we think [self-directed brokerage accounts] will become a more attractive option for retirement investors.” according to BlackRock.

Fidelity is currently the largest 401(k) plan administration firm, accounting for 27% of the U.S. market share. While the firm claims that 38% of its 401(k) participants can take advantage of self-directed 401(k)s, less than 3% actually utilize the option.

Self-directed 401(k)s have been growing in popularity as investors find low-cost options to replace bulky mutual fund holdings. Last year, the Department of Labor enacted a new mandate that requires employers to provide more extensive fee information on 401(k) plans, which lead to rising interest in low-cost alternatives like ETFs.