In the 1990s, Muhlenkamp Fund’s clever value investing formula made it a star among no load mutual funds. Then the long tech bull market left it in the dust. A new generation is making a comeback.Twenty years ago Wexford, PA-based Muhlenkamp Fund was a perennial star on Forbes annual mutual fund Honor Roll list. Year-after-year it bested the S&P 500 using a low risk investment formula seeking large and small cap companies whose return on equity surpassed their price-earnings ratios and whose revenue growth ...