NEW YORK, May 27, 2025 (GLOBE NEWSWIRE) -- OTC Markets Group Inc. (OTCQX: OTCM), operator of regulated markets for trading 12,000 U.S. and international securities, today announced Greenheart Gold Inc. (TSX-V: GHRT; OTCQX: GHRTF), an exploration company, has qualified to trade on the OTCQX® Best Market. Greenheart Gold Inc. upgraded to OTCQX from the OTCQB® Venture Market. Greenheart Gold Inc. begins trading today on OTCQX under the symbol “GHRTF.” U.S. investors can find current financial disclosure and Re ...