(AP) — Incumbent Don Stenberg faces one Republican challenger in bid for re-election as state treasurer.

Since being elected treasurer in 2010, Stenberg says he has cut the office’s budget by 14 percent and improved a state website that details the money Nebraska government spends and receives.

Christopher Costello of Omaha is challenging Stenberg for the GOP nomination. Costello, who has worked in the Douglas County treasurer’s office and now heads a bus company, says he’s concerned about corruption in the tax-collection system.

Michael O’Hara of Omaha is the only Democratic candidate for treasurer. O’Hara, a professor at the University of Nebraska at Omaha who teaches law and economics, says he wants to improve the office’s efficiency and transparency.

Libertarian Michael Knebel of Bellevue is also running.

The primary is May 13.