International credit ratings agency Standard & Poor's has warned it may downgrade Vector's BBB+ credit rating.
The ratings agency's only comment is that it's because it has changed its international rating methodology.
S&P says it has had a conversation with Vector and other affected companies around the globe to explain the potential implications of its revised criteria, as it usually does.
The ratings agency says the rationale for any rating action on Vector will be disclosed publicly when it has made a decision on the company's rating.
Vector says Standard & Poor's has advised it that the reason for the change is because of the ratings agency's assessment of the regulatory regime in New Zealand, which it believes is less stable than other regimes internationally and riskier.
The electricity lines company says it does not believe this change has any immediate financial or customer impact and that it continues to work with the Government and other agencies to establish a more stable regulatory regime.
The Commerce Commission regulates how much electricity lines companies can charge and Vector is facing a regulatory price cut, although the situation is still uncertain with a High Court review of the commission's decision still pending.
Forsyth Barr analyst Andrew Harvey-Green, who doesn't expect any substantive change from the court, says the price cut will have a significant impact on Vector's earnings.
