Credit rating agencies are back on familiar, if not a little uncomfortable territory. In the wake of the credit crisis they were caught out for their inability to predict what the collapse of the sub-prime mortgage market would mean for trillions of dollars in securitisations. Now they are under fire for the opposite: for acting prematurely in the downgrading of eurozone sovereigns.

Standard & Poor's downgraded Greece three notches to BB+, sub-investment grade, on April 27, just five days before the European Union and International Monetary Fund announced their €110bn three-year loans package. Fitch Ratings also acted early, making its downgrade on April 9. That was as spreads on Greek government bonds were widening and risk aversion in the eurozone bond markets was growing.