Growth equity, a somewhat murky investment category residing between venture capital and buyouts, has matured to the point where it deserves to be considered an asset class, says investment adviser Cambridge Associates.

The firm said Wednesday that it will start issuing quarterly benchmark returns for the new class along with those for U.S. venture capital and private equity.

And the data make clear why growth equity is popular—it outperformed venture capital over the crucial 10-year window by nearly six percentage points.

The annual return to limited partners by growth-equity funds for the 10 years ended Dec. 31 was 12.7% versus 6.9% for venture funds.

On top of that, growth equity was much less risky, generating a capital loss ratio of 13.4% compared with 35.4% for venture capital between 1992 and 2008. Significantly, its loss ratio was lower than buyouts' 15.1%.