It was the first time the state high court has taken such an action, and her colleagues could have suspended her or removed her from the bench.

Ziegler ruled in favor of West Bend Savings Bank in several cases she heard as a Washington County judge between 2001 and last year. The court said Ziegler's "serious and significant" offense diminished public confidence in the legal system.

The state's judicial code requires judges to withdraw from cases in which they have a significant financial interest that could raise questions about their impartiality.

Ziegler called her hearing of the cases an "inadvertent error."

"I appreciate that this matter is now concluded," she said in a statement. "I look forward to continuing to serve the people of Wisconsin."

Mike McCabe, director of the watchdog group Wisconsin Democracy Campaign, which filed the complaint, argued that suspension or removal from office would be more appropriate.

"The discipline will be seen by the public as nothing more than a slap on the wrist," McCabe said. "Clearly the court is operating under a cloud right now."

Ziegler, 44, began her 10-year term on the Supreme Court in August.