Despite some anxious days in June, 2013 so far has been a strong period for the stock market. That has contributed to robust one-year and three-year returns for target-date mutual funds—which are all-in-one portfolios for retirement savings.

Looking at just the past three months, however, many funds posted losses. The period saw more pain for bond investors than stock investors. As a result, target-date funds for people in or near retirement—which tend to be heavy on bonds—delivered worse results than stock-heavy funds geared to younger workers.

Target funds for retirement years 2000 through 2010 returned a negative 1.5% on average in the quarter vs. a negative 0.5% for funds for years 2036 through 2040, according to Morningstar.

The bond battering also weighed heavily on funds that tend to have more exposure to bonds than their peers, including Invesco's Balanced- Risk target-date series.

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