Pittsburgh-based midstream partnership EQM Midstream Partners L.P.'s counterparty credit quality has deteriorated due to its largest counterparty EQT's downgrade to 'BB+/Negative'. Additionally, EQM's leverage metrics and distribution coverage remain pressured due to the delay in the Mountain Valley Pipeline project. As a result, we are lowering our issuer credit rating to 'BB+' from 'BBB-'. At the same time we are lowering our issue-level ratings on the partnership's unsecured debt to 'BB+' from 'BBB-' and assigning a '3' recovery rating, based on our expectation for meaningful recovery (50%-70%; rounded estimate: 60%) recovery in a payment default scenario. The negative outlook reflects the uncertainty around both the timing and costs of the Mountain Valley Pipeline's completion and the impact of contract renegotiations