Despite our expectation that Oklahoma City-based Glass Mountain Pipeline LLC will expand its pipeline system and throughput volumes over the medium term, the company's leverage remains high. We are revising our outlook on the company to negative from stable and are affirming our 'B' issuer credit rating. At the same time, we are affirming our 'B' issue-level rating on Glass Mountain Pipeline Holdings LLC's first-lien term loan B. The '3' recovery rating remains unchanged, indicating our expectation for meaningful (50%-70%; rounded estimate: 65%) recovery in the event of a payment default. The negative outlook reflects our forecast that Glass Mountain's debt to EBITDA will remain above 6.5x in 2019 due to delayed volume growth. The negative outlook reflects our expectation