Mediates the Na(+)-independent transport of organic anions such as the thyroid hormones T3 (triiodo-L-thyronine), T4 (thyroxine) and rT3, and of estrone-3-sulfate and taurocholate. Experimental confirmation may be lacking for some isoforms. Ubiquitous, with the exception of spleen and leukocytes. Belongs to the organo anion transporter (TC 2.A.60) family.