Matt Quinn and I were wondering among ourselves Wednesday why Citigroup CEO Vikram Pandit wasn't on the panel of bankers testifying that day before the Financial Crisis Inquiry Commission. After all, Citigroup was arguably the largest basket case of all the banks that got bailed out.

Only half seriously, we decided that perhaps the panel really didn't need to bring Citi in to testify. After all, the government still owns 27 percent of the bank, so all it has to do is get Pandit on the phone to find out what it wants to know. Still, the panel's purpose is part public and based on what we've seen so far from the likes of the Treasury and the Fed in connection with Goldman Sachs and AIG, what's the chance that anything worth knowing will be disclosed?

So the question stands: Where's Citi in all this? And we we're not the only ones who are curious, evidently. In his opening statement, Panel Chairman Phil Angelides noted rather cryptically that Pandit's absence did not mean that the panel had not already interviewed him, or that it had. (Pandit had a good excuse for not appearing on Thursday, as it happened to be his fifty-third birthday.)

But then Matt and I began to wonder why the panel would be satisfied with Pandit when discussing Citi. What about Charles Prince and Robert Rubin, or Sandy Weill, for that matter? Indeed, Pandit inherited most of the mess from his predecessors.

 Now we see that MIT professor Simon Johnson shares our wonderment and has called for a panel of exactly those four witnesses. He points out that the banking problem isn't the fault of individuals, but of the overall system, and Citi has been at the center of a number of crises involving it, so the panel should drill all the way down to the crux by questioning the key people in its history.

As he put it on Thursday, "Citi has been at the center of all major international financial crises over the past 30 years; its alumni have top positions in our administration; and no one thinks it is a well-run organization."