The Senate Banking Committee was re-elected in 2010 and had said he did not plan to run again in 2016. Still, his abrupt departure now was a surprise.
It also will have implications for the Banking Committee, of which DeMint was a member.
The South Carolina Republican has been holding up several banking bills, including one that would protect information provided by banks to the Consumer Financial Protection Bureau. DeMint had insisted that the Senate first take an up-or-down vote on repealing the Dodd-Frank bill.
Sources indicated last week they expect DeMint to drop his hold on the CFPB bill.