Do you know what a 2a-7 put is? If you don't, here's a tip: Don't invest in AIG ( AIG). On Thursday's earnings call, AIG said 2a-7 puts -- whatever the heck they are -- are likely to cost them money at some point. How much money? They don't know. Dan Johnson, an analyst with $20 billion Chicago hedge fund Citadel Investments, asked AIG management about 2a-7 puts in a conference call to discuss the insurer's $5.36 billion second-quarter loss reported after Wednesday's closing bell. Few sane individual investors are familiar with these obscure derivative investments, hedges by AIG counterparties that certain bond investments will fail, which takes their name from a Securities and Exchange Commission rule. But Citadel's interest in them speaks to their import, as the firm is one of the few institutions that may be a match for Goldman Sachs ( GS) in the brains department. If the above illustration of the complex instruments AIG is involved with doesn't convince investors they are better off at the blackjack tables than investing in the insurer, perhaps nothing will. AIG is not alone, of course. It is merely plagued by the same virus that has infected a great number of the large financial companies around the world: Its business is way too complex, and investors are running for the hills from them until they can clearly and honestly explain what they're worth. The transcript of the conference call does little to clarify the situation. Citadel's Johnson asked AIG management about 2a-7 puts based on something he found buried on page 87 of the insurance giant's quarterly earnings report. Elias Habayeb, CFO of AIG Financial Products, a derivatives-trading AIG subsidiary, told Johnson "we do have 2a-7 puts that continue to be outstanding, and given the current state of the market, we would be expecting to be buying back those underlying reference obligations."