 NEW YORK, June 18, 2021 PRNewswire -- OTC Markets Group Inc. OTCQX: OTCM, operator of financial markets for 11,000 U.S. and global securities, today announced Hochschild Mining PLC LSE: HOC: OTCQX: HCHDF, an underground precious metals producer, has qualified to trade on the OTCQX Best Market. Hochschild Mining PLC upgraded to OTCQX from the Pink market. 