"Downward rating pressure could occur if we expect debt to EBITDA to sustain above 3x, due to cost overruns or project delays that impair the group's cash flow generation."
A credit down-grade could be a serious blow given SkyCity's current rating is BBB- - only just considered to be investment grade - anything below that could make it harder and more expensive for the company to raise debt.
SkyCity investors also got some surprise news with a potental buy back of 5 per cent of its shares which could be worth around $135 million.
S&P said Sky should have sufficient balance sheet strenth to absorb the buy-back cost without its rating changing but said it was a negative from a credit perspective.
It also noted that the full buyback was dependent on the sale of the Auckland car park.
S&P expectes SkyCity to net $228 million from the sale of the car park and its Darwin Casino.
Given it has already revealed it will get around $200m from the Darwin sale meaning the Federal St car park deal is likely to net around $28m or around $14,000 for each of its 1960 car parks.