Fitch Ratings has upgraded People’s United Financial, which has subsidiary branches throughout Massachusetts and New England, to reflect stability of operating performance, sustainability of asset quality metrics and its strong capital position.

The long-term Issuer Default Ratings (IDRs) of People’s United and its subsidiaries have been upgraded to ‘A-‘, and the bank’s short-term IDR was affirmed at ‘F1’. The rating outlook is stable, Fitch said.

Fitch assigned a positive outlook to People’s United ratings in June 2007 after the announcement of a definitive agreement to acquire Chittenden Corp., which closed Jan. 1, 2008. The bank underwent a two-step conversion to a publicly traded bank from a mutually held institution. As a result of the public offering, it amassed a sizable amount of capital to deploy.

The stable outlook reflects Fitch’s view that PBCT will exhibit strong operating performance, a modest, albeit at a manageable level, increase in delinquencies and charge-offs from its loan portfolio, and continued conservative capital management, Fitch said.