Enables phosphatidylinositol-3,4-bisphosphate 4-phosphatase activity. Acts upstream of or within inositol phosphate dephosphorylation and phosphatidylinositol dephosphorylation. Predicted to be located in Golgi apparatus. Predicted to be active in cytoplasm. Orthologous to human INPP4B (inositol polyphosphate-4-phosphatase type II B). [provided by Alliance of Genome Resources, Apr 2022]