...+ U.S.-based oil and gas exploration and production company Northern Oil & Gas Inc. has announced the completion of its exchange for a portion of its unsecured notes for a combination of equity and new second-lien secured notes. + We are lowering the corporate credit rating on Northern Oil & Gas to '##' from '##'. + We are also lowering the issue-level rating on the company's senior unsecured notes to 'D' from '##'. DALLAS (S&P Global Ratings) May 16, 2018--S&P Global Ratings today lowered its corporate credit rating on Northern Oil & Gas Inc. to '##' (selective default) from '##'. At the same time, we lowered the issue-level rating on the company's senior unsecured debt to 'D' from '##'. We will review our recovery ratings on the company's debt, including recovery ratings, when we view the likelihood of further exchanges to be low. The downgrade follows the announcement by Northern Oil & Gas that it has completed its exchange, which includes the exchange of about $500 million in unsecured...