Acts as a membrane potential-dependent organic anion transporter, the transport requires a low concentration of chloride ions (PubMed:22460716). Mediates chloride-dependent transport of urate (PubMed:22460716). Mediates sodium-independent high affinity transport of thyroid hormones including L-thyroxine (T4) and 3,3',5-triiodo-L- thyronine (T3) (PubMed:30367059, PubMed:34937426). Can actively transport inorganic phosphate into cells via Na(+) cotransport (PubMed:22460716). {ECO:0000269|PubMed:22460716, ECO:0000269|PubMed:30367059, ECO:0000269|PubMed:34937426}. This is the function of SLC17A4 (solute carrier family 17 member 4, ENSG00000146039).