Question about IMAX aspect ratios

Just came out of the theatre after watching Wicked in IMAX. I'm aware that most IMAX screens are now 1.90:1, but I still saw horizontal black bars on the top/bottom, albeit not as tall as the ones you'd see off of a home release (which would likely be 2.39:1).

Was that a stylistic choice by the movie studio, or was there some sort of cropping involved despite being intended for IMAX screens?