As a whole, investors should welcome attempts to safeguard the integrity of markets. You need very clear rules applied to markets.

It is hard to imagine that, having downgraded the US, S & P will not follow suit on at least one of the other members of the dwindling club of sovereign AAAs. If this were to materialise and involve a country like France, for example, it could complicate the already fragile efforts by Europe to rescue countries in its periphery.

For the next three years, we're going to see different economies work out different problems. For European economies, especially Greece, it would be through default.

Mohamed El-Erian Quotes