Efficiency gains also drove results at the Kansas City, Mo., company.
Shelley Siefert will also become the bank's president in May.
The Illinois company will become one of the area's top 10 banks after buying Bank of Edwardsville.
Fountain City Fintech, a program planned by NBKC Bank, would be one of the first fintech incubators formed by a community bank.
The company will gain 10 branches and $145 million in loans after it buys Gideon Bancshares.
The investment bank agreed to buy Business Bancshares in St. Louis.
The Missouri company reported strong loan growth that also reflected a spike in factoring activity.
The Illinois company has agreed to buy Springfield Bancshares for $87 million.
The deal for Retirement Plan Services, which provides recordkeeping for employers nationally, is NBT's fourth acquisition of a retirement services firm since 2015.
David Kemper is set to hand the reins over to his son, John, this summer.