In addition to the loss of all principal put into Madoff, and not withdrawn, after early 2004, the losses include all appreciation on that principal since 2004. In terms of this case, those losses are called the appreciation shown on account statements from Madoff, and are in the mucho billions, although once again only Picard and the government know their amount. And, even if one follows Picard and says these were not truly losses because the appreciation was phony and losses therefore should not be measured by the legitimate expectations shown on the statements of November 30th, losses still exist in the billions of dollars because of what the economists call opportunity costs. Which is to say that, had the money not been invested in Madoff, it would likely have been invested elsewhere and earned interest and appreciation. (Since so many Madoff investors were essentially conservative investors, their market losses of principal in 2008-09 might not have been too bad because they might have been heavily in Treasuries or bonds that maintained their value. As well, any partial losses of principal would have been partially recouped in recent months and might be still further recouped in future. And, in any event, interest was lost -- my understanding is that a New York law sometimes sets interest in pertinent cases at nine percent -- that's a hell of a chunk of change over the years. Even interest at three to five percent would be a major chunk of money.)
Taxes were also lost. Take the question of federal income taxes paid on phony profits since 2004. According to the rules followed, or imposed, by the IRS, refunds can be obtained for those taxes for only three or five years, depending on the taxpayer's circumstances. (I think I am right about five years.) So, as I understand it, according to the IRS, refunds can be obtained only for taxes paid on phantom profits from 2005 onward or 2003 onward. But suppose the IRS had exposed the scam in 2004. In that case, not only would one not have paid income taxes in phony profits from 2004 onward, but, even according to the IRS, refunds would have been obtainable for the years 2001-2003 or 1999-2003 -- refunds of doubtlessly billions of dollars which are not available now according to the IRS.
In addition, theft deductions could have been carried back for earlier years than are now available had the IRS blown the whistle on Madoff in 2004, and there are people who would not have paid huge sums in estate taxes from 2004 onward because large chunks of the supposed estate would have been known not to exist.
So, as said, the amount of tax money that was lost by investors, due to the IRS' failure to catch and expose Madoff in 2004, must be gigantic even if not currently known to the public. Also, what this additionally means is that not only are losses since 1992 partially attributable to one government agency, the SEC, because of its moral and criminal incompetence then and later and because its unbelievable 1992 public statement that there was no fraud made it a co-cause with Madoff of sucking people into his scam, but a second government agency, the IRS, is partly responsible for all losses since 2004 because its malfeasance enabled Madoff to successfully continue his scam from then until nearly the end of 2008. And the fact that two government agencies, not just one, bear heavy responsibility for the success of the scam and the losses of investors makes it even more appropriate for the government to take action to relieve their plight, which it has not yet done for the most part. (Nor -- with only one exception that I know of (a complaint filed against FINRA which assails it for general incompetence or worse with regard to far more than Madoff) -- has anyone really considered in this regard that the malfeasance and incompetence of a body set up by a federal statute, FINRA, also was a contributing factor to the success of the scam from the very beginning of the fraud, whenever that was. Except for the one complaint which attacks it for a wide variety of failures in addition to its failure in Madoff, FINRA has thus far gotten pretty much a free pass in the Madoff disaster. It bears heavy responsibility, however, and most certainly should not get a free pass.
One must add that, even though the IRS bears responsibility for extensive losses, and a fellow government agency bears responsibility for all losses since 1992, the government -- the IRS -- wants to keep the lion's share, in years, of the taxes which were paid to it but should not have been because they were paid on phantom income, on phony income -- on money the government does not even have the constitutional authority to tax because its constitutional power is only to tax real income, not phantom income. The IRS is allowing people to recover refunds for only three or five years, and, if people wish to use its safe harbor provision for theft deductions, they have to give up the right to assert various doctrines that would allow them to obtain refunds of income taxes paid before that, e.g., refunds on taxes wrongly paid at least back to the early 1990s when the scam is known to have already been in operation. So not only is the IRS one of the causes of investors' losses, but it demands to keep more than a decade of taxes that should never have been paid (and it does so though it reserves the right to collect back to infinity if the shoe is on the other foot).