Since 2012, 10 credit unions have purchased 11 banks. And in 2016, two new deals were announced and one acquisition was completed.

What's more, three additional deals are in the making and could be announced in the near future, according to Michael M. Bell, a Royal Oak, Mich.-based attorney, who has been involved in 10 of the credit union bank acquisition deals.

While it's difficult to project whether credit union bank acquisitions will become a trend with traction in the years to come, Bell and other industry experts said buying a bank can be a growth option for some credit unions with strong capital positions. According to Bell, the typical ROI ranges from one to three years.