Eight UCP leadership candidates had until 5 PM to officially register for the race to succeed Jason Kenney.
Applicants were required to hand in 1,000 signatures from the province’s five regions and the first $75,000 of the $175,000 contest fee.
Only Calgary businessman Jon Horsman pulled out from the race.
In a social media post on Wednesday, Horsman said his campaign was “on track” to meet the deadline, but he decided to withdraw because it is a “very crowded leadership race.”
“Having one more (candidate) does not serve the purpose of why I decided to run — which was to contribute to the success of the conservative movement in Alberta by growing the moderate and inclusive base for the party,” Horsman wrote.
“As I stand down today, I stand ready to move forward with the UCP through future opportunities.”
Front runners Travis Toews, Danielle Smith and Brian Jean are joined by Leela Aheer, Todd Loewen, Rajan Sawhney, Rebecca Schulz and Raj Sherman.