This makes great deal of sense: We believe the crisis was the product of 10 factors. Only when taken together can they offer a sufficient explanation of what happened: Starting in the late 1990s, there was a broad credit bubble in the U.S. and Europe and a sustained housing bubble in the U.S. (factors 1 and 2). Excess liquidity, combined with rising house prices and an ineffectively regulated primary mortgage market, led to an increase in nontraditional mortgages (factor 3) that were in some cases deceptive, in many cases confusing, and often beyond borrowers' ability to pay. However, the credit bubble, housing bubble, and the explosion of nontraditional mortgage products are not by themselves responsible for the crisis. Our country has experienced larger bubblesthe dot-com bubble of the 1990s, for examplethat were not nearly as devastating as the housing bubble. Losses from the housing downturn were concentrated in highly leveraged financial institutions. Which raises the essential question: Why were these firms so exposed? Failures in credit-rating and securitization transformed bad mortgages into toxic financial assets (factor 4). Securitizers lowered the credit quality of the mortgages they securitized, credit-rating agencies erroneously rated these securities as safe investments, and buyers failed to look behind the ratings and do their own due diligence. Managers of many large and midsize financial institutions amassed enormous concentrations of highly correlated housing risk (factor 5), and they amplified this risk by holding too little capital relative to the risks and funded these exposures with short-term debt (factor 6). They assumed such funds would always be available. Both turned out to be bad bets. These risks within highly leveraged, short-funded financial firms with concentrated exposure to a collapsing asset class led to a cascade of firm failures. The losses spread in two ways. Some firms had large counterparty credit risk exposures, and the sudden and disorderly failure of one firm risked triggering losses elsewhere. We call this the risk of contagion (factor 7). In other cases, the problem was a common shock (factor 8). A number of firms had made similar bad bets on housing, and thus unconnected firms failed for the same reason and at roughly the same time. A rapid succession of 10 firm failures, mergers and restructurings in September 2008 caused a financial shock and panic (factor 9). Confidence and trust in the financial system evaporated, as the health of almost every large and midsize financial institution in the U.S. and Europe was questioned. The financial shock and panic caused a severe contraction in the real economy (factor 10). We agree with our colleagues that individuals across the financial sector pursued their self-interest first, sometimes to the detriment of borrowers, investors, taxpayers and even their own firms. We also agree that the mountain of government programs supporting the housing market produced distorted investment incentives, and that the government's implicit support of Fannie Mae and Freddie Mac was a ticking time bomb. But it is dangerous to conclude that the crisis would have been avoided if only we had regulated everything a lot more, had fewer housing subsidies, and had more responsible bankers. Simple narratives like these ignore the global nature of this crisis, and promote a simplistic explanation of a complex problem. Though tempting politically, they will ultimately lead to mistaken policies. Thomas, Hennessey and Holtz-Eakin: What Caused the Financial Crisis? - WSJ.com Many of us here have said there were multiple factors and that regulation aimed at one Blame Recipient is misguided.