Although an entire series of target date funds may be marketed to retirement plan sponsors, they may decide to choose only a few funds out of the series. So say data from a new analysis of 401(k) recordkeeper platforms released Tuesday by the Financial Research Corporation (FRC).

The FRC study was released at the same time that Morningstar completed its quarterly review of target-date fund family ratings, and some changes were made—including a downgrade for powerhouse target-date provider Charles Schwab.

Morningstar, in its quarterly review of target-date fund family ratings, downgraded Schwab to Below Average from Average because of the sudden departure of its previous manager "and the lack of clear, long-term succession plan." While an interim manager from Schwab's collective trust group has been named, Morningstar said, "there is currently a great deal of uncertainty about what this series will look like in the future."