Geometrically frustrated systems exhibit intriguing physical phenomena under applied magnetic fields. The rare-earth tetraboride (RB \(_4\) , R is a magnetic rare-earth) family, a Shastry–Sutherland frustrated magnetic system, displays plateaus at fractional values of the saturation magnetization. Because of its metallic character, \(\textit{R}\text {B}_4\) could be an ideal platform for investigating the interplay between conduction electrons and fractional plateau phases. Here, we investigate the electrical transport of \(\text {HoB}_4\) , which is a member of the \(\textit{R}\text {B}_4\) family that possesses fractional magnetization plateaus. We observe pronounced peak-like features and a violation of Kohler’s rule in the magnetoresistance associated with the complex magnetic phases. In addition, we identify a distinct hump-like anomaly in the Hall resistivity corresponding to the fractional plateau phases. We propose that the hump-like feature is most likely a manifestation of the topological Hall effect, arising from the real-space accumulation of Berry curvature due to non-coplanar spin textures. Our work provides new insights into the origin of the fractional magnetization plateaus in \(\text {HoB}_4\) and serves as a useful reference for understanding frustrated magnetism in metallic systems.
