The transition is over. Henry Ellenbogen, who succeeded Jack Laporte at the helm of T. Rowe Price’s $16.2 billion New Horizons Fund on March 1, 2010, has fine-tuned the portfolio into his own. So far, so good. Under Laporte, the fund’s average annual gain of 9.6% over more than 23 years ranked in the top 29% of its small-cap growth peer group. Ellenbogen has racked up a 22.97% average annual gain.