How much exposure do they have to the financial sector ? As in 2008, we should be wary of cross-pollination.

The limits on the banks' exposures are dependent on counter party risk. GS's exposure is far more, but they insured most of it with other banks, and please allow me the simplifying assumption they insured all of it with BAC. Which means that (hypothetical scenario) if BAC goes bankrupt, suddenly GS exposure to oil goes up to, say $100BB. Suddenly the reserves are woefully insufficient. Then there's the sudden risk that GS goes belly-up, which would increase everyone else's exposure. One of them goes and ...

Additionally, oil fuels the economy. Oil is what builds the roads, what makes everything on the roads moving, what keeps planes in the air and boats going forward. Oil provides significant parts of our electricity supply, and so on and so forth. So you can look at the oil sector problem in 2 ways. Either you look at the supply side, which is producing somewhere around 2% more oil than the market is willing to buy (at any price). This is short-sighted. "If we'd all just put 2% more gas in our tanks, there wouldn't be a problem", which is not realistic.

The other oil to look at is demand-side oil. The market is simply not buying 2% of the oil, except to store it. Why not ? One explanation would be that there is a global recession and the oil price move is simply the result of that. The fact that the price crash happened with oil production/supply constant (even slightly declining) would seem to support this. For instance the baltic dry index plunged before oil started having problems, same with container shipping, and this explains quite a bit of the excess capacity in oil, and therefore, I say caused the price drop in oil. Oil crashed because manufacturing (the source of the demand for shipping) crashed a few months before the oil crash (and hasn't recovered).

In other words : you've identified the wrong problem. Oil is a symptom of the underlying situation, not a cause. You say banks are capable of withstanding one aspect of a greater problem ? Well, I'm not saying that's bad, but it's not reassuring at all (and may not be true due to financial engineering).