What does 'negative watch' on Viability Rating mean for PNB?

Following the $1.77-billion fraud, PNB's Viability Rating of 'bb' was put on 'Rating Watch Negative' by Fitch on Tuesday. The Viability Rating measures the creditworthiness of a financial institution and reflects the likelihood of the entity to fail. A 'negative watch' status is given when the rating agency is deciding if the company's Viability Rating will be lowered.