(MENAFN- ProactiveInvestors)Midstates Petroleum (OTCMKTS:MPOY) shares dropped by as much as 16% on Monday after S&P Ratings downgraded the company's credit and issue-level ratings to D from triple C minus on a missed interest payment. The U.S.-based oil and gas exploration and production company announced that it has elected not to make its interest payment on its 10.75% senior notes due 2020. "We believe it is likely the company will file for Chapter 11 to  restructure the company. As a result we are lowering our corporate credit ratings and issue-level ratings on Midstates' debt to 'D'" S&P said. Midstates shares ended on Monday down 3.2% at $0.30.