The implementation of the Labor Department's fiduciary rule is set to upend fee structures and the manner in which advisors manage their practices.

The rule, which governs certain kinds of retirement advice, such as rollovers, has shone a spotlight on the $24 trillion retirement investment market. Of that amount, assets in IRAs total more than $7 trillion, making IRAs one of the most popular investment vehicles for retirement.

With the new fiduciary rule pending, we examine key statistics that characterize the current IRA market. Click here to view a slideshow version. - Nicholas Yeap