Johnson Bank is closing a branch in the Cayman Islands that opened in 1998 to facilitate overnight deposit transactions for what the bank called a limited number of large commercial customers.

The Johnson Bank branch in Grand Cayman handles so-called Euro-sweep accounts. American banks typically offer an overnight investment into a U.S. dollar account held in a Cayman Islands branch. Banks convert the funds into higher-yielding savings or investment instruments.

Johnson Bank is not required to provide collateral for the transactions and the funds in the branch do not count toward the bank’s reserve requirements, according to a letter Johnson Bank submitted to the Wisconsin Department of Financial Institutions and the Federal Reserve Bank of Chicago. The Cayman Islands office will close by Dec. 31.

Johnson Bank is owned by Johnson Financial Group, Racine.

“The branch is being closed due to changes in the Johnson Financial Group Inc. corporate structure and changes in U.S. banking law which now allows interest to be paid on commercial deposit accounts,” Johnson Bank senior vice president John Topczewski said in the letter.

Johnson Financial Group and Johnson Bank named new top management in July, including new CEO Tom Bolger, formerly of Harris Bank. The family that owns S.C. Johnson & Son Inc. and Johnson Financial announced Nov. 1 it was investing $235 million to shore up the family’s Johnson Financial Group and Johnson Bank.