The rating agencies are being constantly criticised for being too slow to act; for being behind the curve. Yet European leaders have been incensed by the rating agencies downgrading the likes of Greece and Spain, so much so, that there are strong calls for the establishment of a European rating agency.One wonders what such an agency would do, when the European Central Bank, responding to criticism that it has been buying poor quality bonds to support struggling euro zone members, retorted that the bonds are only poor quality in the eyes of the rating agencies.Anyway, being quick off the mark, Moody's downgraded Greece to junk on Monday night: S&P did this in late April and Fitch moved Greece down to one notch above junk in early April. The markets responded poorly to the news with the Dow Jones shedding the 117 points it had gained in early trading, to finish the day 25 points down.Moody's was concluding the review for possible downgrade that it initiated on April 21. It lowered its long-term rating assigned to Greece by four notches to 'Ba1' and cut the short term rating to Not-Prime (NP) from Prime -1 (P1).Moody's said it left the outlook on Greece's ratings at stable to reflect the substantial probability that the rating will not change over the next 12 to 18 months.