I recently read Boomerang, a 2011 book by Michael Lewis based on magazine articles he wrote in 2009, 2010 and 2011. These articles looked at Iceland, Ireland, Greece, Germany and the United States in the aftermath of the financial crisis. I generally like Lewis as a writer and I found the book entertaining and a useful reminder that the excesses that led to the financial crisis were not confined to the United States.
In Iceland the problem was the banks. They grew extremely large (compared to the economy of Iceland) by making lots of bad loans around the world. The rapid growth should have been a red flag as credit worthy borrowers are a scarce resource that other banks will compete strongly for. This makes it hard for a bank to grow rapidly while maintaining high loan standards. Obviously there is less competition for bad credits so it is easier for a bank to grow rapidly if it makes a lot of low quality loans. But this generally doesn't work out too well in the long run.
In Ireland the problem was an amazing property and construction boom which Irish banks fueled with easy credit. When the bubble inevitably popped the banks became insolvent and would have failed had not the Irish government made a dubious and extremely costly decision to guarantee all their debt. In the US there is a lot of loose talk about taxpayer dollars bailing out the banks but in fact the government profited overall by supporting the banks (since as it turned out they were fundamentally sound). This was not the case in Ireland.
In Greece the problem (as least as related by Lewis) is that the Greek people individually and collectively are not credit worthy. So it was a big mistake to admit Greece to the Euro as this gave the false impression that Greece was credit worthy. So a lot of bad loans were made to Greece.
The German problem was a little different. Germany was saving more money than could be productively invested in Germany. So the German banks looked to invest abroad. Foreign investing can work out but you have to be careful you don't get stuck with a bunch of garbage the locals have sensibly passed on. The German banks failed to be adequately cautious thereby acquiring a lot of bad loans and a worldwide reputation for stupidity.
I thought the final chapter on the United States was the weakest in the book. Lewis discusses the financial problems of some state and local governments but in a big country like the United States there will always be some problems. Lewis doesn't really make the case that these problems threaten the country as a whole.
So in summary I can recommend the book as a good example of its genre.
6 hours ago