The NCUA approved 23 mergers in July in 18 states, bringing the total number of approved mergers to 155 for 2013.

Four of July's mergers occurred in California and all but one of the credit unions had assets of less than $50 million, according to NCUA's monthly Insurance Activity Report posted in late August on the regulator's website.

Sixteen of the small credit unions merged with larger counterparts to expand services to members, while only one merged because it was in poor financial condition and two consolidated due to the "inability to obtain officials" or were unable to find a new CEO, according to the NCUA report. One credit union merged because it lost its sponsor, one consolidated due to a loss or declining membership, one merged because of lack of growth and one consolidated with a state-chartered credit union.