Sam Smith is a close second earning 13 nominations including nods in some of the night's biggest categories including Top Male Artist, Top Artist, Top Billboard 200 Album and Top Hot 100 Song.

Iggy Azalea and Meghan Trainor round out this year's biggest nominees with 12 and nine nominations, respectively. Both are nominated for Top New Artist alongside 5 Seconds of Summer, Hozier and Sam Smith.

While winners at the Billboard Music Awards are based on album and digital song sales, radio airplay, streaming, touring and social-media interactions, there is one category, the Billboard Chart Achievement Award, that the fans get to decide. This year's nominees for that prize include Azalea, Trainor and Swift.