OTC Markets Group Welcomes Pioneer Energy Services Corp. to OTCQX PR Newswire NEW YORK, Aug. 15, 2019 NEW YORK , Aug. 15, 2019 /PRNewswire/ -- OTC Markets Group Inc. (OTCQX: OTCM), operator of financial markets for 10,000 U.S. and global securities, today announced Pioneer Energy Services Corp. (OTCQX: PESX), a provider of contract land drilling, well servicing, wireline, and coiled tubing services, has qualified to trade on the OTCQX® Best Market. Pioneer Energy Services Corp. previously...