Moody's Investors Service has affirmed the "VMIG 1" short-term ratings on Chicago-based Northwestern Memorial HealthCare's series 2007 A-1, A-2, A-3, A-4 and series 2008 A-1 and A-2 bonds.
The ratings are based on several factors, including the credit quality of TD Bank, JP Morgan Chase Bank and Northern Trust, which support the bonds.