In its announcement, S&P stated that the upgrade in OPG's long-term rating reflects a "closer relationship between the company and its higher-rated owner, the Province of Ontario (AA/Stable/A-1+); and a slightly stronger stand-alone credit profile, given regulatory support and an expected improvement in cash flow metrics".
In addition, it was noted that regulatory oversight by the Ontario Energy Board with respect to establishing regulated prices for OPG's baseload nuclear and baseload hydroelectric assets, a diverse generation portfolio, and cost-competitive position support OPG's strong business risk profile.
In September 2005, S&P affirmed OPG's long-term corporate credit rating at BBB+ and revised its outlook to "positive" from "developing".