...NEW YORK (S&P Global Ratings) July 27, 2016--S&P Global Ratings today said it assigned its '##-' senior unsecured debt rating on Navient Corp.'s (##/Negative/B) $750 million senior unsecured notes due in 2021. The debt rating is one notch below the counterparty credit rating because Navient's tangible unencumbered assets are less than its outstanding unsecured debt. We exclude from unencumbered assets the company's overcollateralization balances associated with its asset-backed securities trusts. We expect Navient will use proceeds from the issuance to repay senior unsecured debt with nearer-term maturities. Although our ratings and outlook on Navient are unchanged at this time, we view the demonstrated access to the unsecured debt markets and expected use of proceeds favorably. We expect Navient's portfolio of student loans will produce substantial and stable cash flows; however, the majority of its loan portfolio is encumbered by secured borrowings. The negative outlook reflects that...