Spectra of SN 2016hnk at three different epochs (around maximum, after a week, and around three weeks past maximum light) compared to other subluminous 1991bg-like SNe Ia, PTF09dav (Ca-rich), and SN 2002es (2002es-like SN Ia). The main typical features of 1991bg-like SNe Ia are identified in the top panel. Vertical lines in the top panel are located at the minima of a few features and serve as a comparison of the velocities with respect other objects. All spectra have been Milky Way extinction-corrected and shifted to the rest frame.