OTC Markets Group Welcomes Superior Energy Services, Inc. to OTCQX PR Newswire NEW YORK, Oct. 4, 2019 NEW YORK , Oct. 4, 2019 /PRNewswire/ -- OTC Markets Group Inc. (OTCQX: OTCM), operator of financial markets for 10,000 U.S. and global securities, today announced Superior Energy Services, Inc. (OTCQX: SPNV), a company which serves the drilling, completion and production-related needs of oil and gas companies, has qualified to trade on the OTCQX ® Best Market. Superior Energy Services...