Sodium-independent transporter of chloride and iodide (PubMed:10192399, PubMed:11932316, PubMed:12107249, PubMed:16684826, PubMed:24051746). Mediates electroneutral chloride-bicarbonate, chloride-iodide and chloride-formate exchange with 1:1 stoichiometry (PubMed:10644529, PubMed:15155570, PubMed:24051746, PubMed:35601831). Mediates electroneutral iodide-bicarbonate exchange (By similarity). {ECO:0000250|UniProtKB:Q9R155, ECO:0000269|PubMed:10192399, ECO:0000269|PubMed:10644529, ECO:0000269|PubMed:11932316, ECO:0000269|PubMed:12107249, ECO:0000269|PubMed:15155570, ECO:0000269|PubMed:16684826, ECO:0000269|PubMed:24051746, ECO:0000269|PubMed:35601831}. This is the function of ENSG00000091137 (SLC26A4, solute carrier family 26 member 4).