For all of the uncertainty and choppiness in the market right now, maybe the single biggest question mark in the near future is the fragile state of the Greek economy. The threat of a Greek default is sending ripples of concern throughout Europe and around the world. While European leaders negotiate the wisdom of another rescue package to stave off a default in the near term, the issue is not going away anytime soon. In fact, many informed observers–including former Federal Reserve Chairman Alan Greenspan–think that it is not so matter of if, but when. And the problem is by no means limited to Europe. Here in the U.S., some might not fully appreciate the gravity of the situation in terms of a potentially dramatic impact on our own financial future. The problem is this: while 94% of the direct losses resulting from Greece defaulting on its debt will fall on European creditors (with only 5% or so of direct losses on the U.S. ledger), American firms were responsible for assuming a large percentage of the insurance on all that Greek debt. U.S. firms will be responsible for approximately 56% of the default insurance payouts triggered by a default (versus only 43% on European firm). The result is that once you factor those insurance obligations into the equation, financial institutions in the U.S. have just as much to lose as those in places like France and Germany. That is a grave concern, and is likely one of the biggest factors behind what has been–and, for the next few months at least, will almost certainly continue to be–a skittish and volatile marketplace.