OREANDA-NEWS. Fitch Ratings has affirmed the following classes of notes issued by Ally Auto Receivables Trust 2015-SN1:

-- Class A-2A: affirmed at 'AAAsf'; Outlook Stable;
-- Class A-2B: affirmed at 'AAAsf'; Outlook Stable;
-- Class A-3: affirmed at 'AAAsf'; Outlook Stable;
-- Class A-4: affirmed at 'AAAsf'; Outlook Stable;

KEY RATING DRIVERS
The affirmation of all outstanding class A notes reflects loss coverage levels consistent with the current ratings. Hard credit enhancement (CE) has grown for all classes since close. Credit and residual losses have been within Fitch's initial expectations to date. The Stable Outlooks reflect Fitch's expectation that the notes will remain sufficiently enhanced to cover stressed loss levels consistent with their current rating levels.

Fitch will continue to monitor economic conditions and their impact as well as trust level performance variables and update the ratings accordingly.

RATING SENSITIVITIES
Unanticipated decreases in the value of returned vehicles and/or increases in the frequency of defaults and loss severity on defaulted receivables could produce loss levels higher than the base case. This would likely result in declines of CE and loss coverage levels available to the notes.

At the time of initial rating, Fitch conducted a sensitivity analysis by increasing the transaction's initial base case residual value (RV) and credit loss assumptions and examining the rating implications on all classes of issued notes. The increases to the base case losses are applied such that they represent moderate (1.5x) and severe (2.5x) stresses, and are intended to provide an indication of the rating sensitivity of notes to unexpected deterioration of a trust's performance.

DUE DILIGENCE USAGE
No third-party due diligence was provided or reviewed in relation to this rating action.