...+ U.S. midstream energy master limited partnership Summit Midstream Partners L.P.'s adjusted leverage is forecast to remain in the 4x-5x range following the partnership's announced $300 million series A perpetual preferred unit offering. The unit offering satisfies a large percentage of the partnership's deferred payment obligation due in 2020, which we previously treated as debt. + As a result, we are raising the partnership's corporate credit and issue-level ratings to '##-' from 'B+'. The outlook is stable. The '4' recovery rating on the partnership's unsecured debt is unchanged. + We are also assigning our 'B-' issue-level rating to the partnership's series A perpetual preferred units. + The stable rating outlook on Woodlands, Texas-based Summit reflects our expectation for adequate liquidity and a strong contractual foundation with minimum volume commitments and limited commodity risk, resulting in adjusted debt to EBITDA of about 5x in 2018, improving to about 4.5x in the long-term....
