Vanguard Primecap Fund Adds Performance Measure to Fees and Then Takes Off

Fund's fourth quarter rally could result in higher expense ratio under new fee structure

A classic case of bad timing may lead to higher management fees at one of Vanguard’s most storied mutual funds.

The trustees for the Vanguard Primecap Fund voted in November to change the way the fund pays its long-time adviser, Primecap Management Co. of Pasadena, California, according to recent regulatory filings. Going forward, Vanguard Primecap’s bas…