Credit union mergers have slowed down so far this year, but industry experts expect the pace of consolidations to pick up over the next five years, bringing the total number of credit unions from today's approximate count of 6,100 to 4,000 by 2020.

From January to September 2015, the NCUA approved 178 mergers, which represents a fall from the 193 approved consolidations that took place from January to September 2014, and the 190 consolidations during the first three quarters of 2013. What's more, the NCUA's recently released approved mergers for October 2015 show only 19 consolidations were given the green light compared to 28 in October 2014 and 24 in October 2013.

And, in November and early December, approximately 12 credit unions have publicly announced the completion of consolidations or new merger agreements, including the $19 billion PenFed Credit Union in Alexandria, Va., which completed three consolidations with military cooperatives based in Dallas and Fort Worth, Texas and Hawaii. The consolidations will also expand PenFed's international operations.