Small-cap and mid-cap domestic equity mutual funds are leading the way in terms of returns so far in 2010, according to an analysis by Standard & Poor’s.

Small-cap value was the best-performing sector as of April 1, S&P said in a report issued Tuesday, with value-oriented mutual funds outperforming growth funds in every cap size. Small-cap value returned 10.4%, while mid-cap value brought in 9.4%. Large-cap growth returned 4.8% and multi-cap growth returned 5.6% over the same period.

S&P identified two small-cap value funds and two mid-cap value funds that have performed the best so far in 2010.  The American Beacon Small Cap Value Fund returned 11.6% and the Fidelity Small Cap Discovery Fund returned 10.6%; both funds also outperformed their peers in 2008 and 2009, and have below average expense ratios.

Meanwhile, on the mid-cap front, Delafield Fund and the Van Kampen American Value Fund brought in 11.3% and 9.9%, respectively. These funds’ expense ratios are “modestly” lower than their sector’s average; both funds’ performance has been above average compared to their three- and five-year benchmarks.