OMAHA, Neb. (AP) — Omaha banker Sid Dinsdale — the wealthiest candidate in a five-man Republican race for U.S. Senate — has loaned his campaign $1 million in the final weeks of the May 13 partisan primary.

The loan by Dinsdale, chairman of Pinnacle Bank founded by his family, places him second in fundraising to Midland University President Ben Sasse in the GOP primary. It also indicates the race for the GOP nomination may be tightening.

Dinsdale’s campaign had said last month that it planned to put more campaign ads on Nebraska airwaves in the days leading up to the primary election, and released a new one Sunday.

Others in the GOP primary are former Nebraska State Treasurer Shane Osborn, Omaha attorney Bart McLeay and Fort Calhoun hotel owner Clifton Johnson.