Costa Mesa-based Pacific Mercantile Bancorp was among the 194 U.S. companies added to the Russell 2000 index when the list of smaller stocks went through an annual readjustment today.

The Russell 2000 is one of the several indexes maintained by Seattle-based Russell Investment Group, which ranks U.S. common stocks in various categories based on market value.

Companies in the Russell 2000 index reflect market capitalizations ranging from $101 million to $2.61 billion.

Pacific Mercantile had a market value of $108.9 million at the end of today’s trading.

Irvine-based Tilly’s Inc. was another addition to the index.

The action-sports retail company went public last month, and now has a market value of about $415.1 million.

A batch of Orange County-based companies was deleted from the index. Santa Ana-based Identive Group Inc. and BioLase Technology Inc. in Irvine both fell off after one-year stays on the index.

Anaheim-based Pacific Sunwear of California Inc., Santa Ana-based Powerwave Technologies Inc., Smith Micro Software Inc. in Aliso Viejo, and Peregrine Pharmaceuticals Inc. in Tustin were other local companies that were deleted.