Just to keep the books on the scam would take dozens of people.
It IS possible for one person to generate all the fake data, trade tickets, individual account reports, etc, via the use of complex programming, especially since it’s quite clear from the 2005 Markopolos document and the SEC’s non-response to it that nobody, and I mean NOBODY was doing any cross-checking of the reported data/tickets/custodial holdings, etc. However, it is absolutely NOT plausible that this was done by 70-year-old Bernie, whose background shows no evidence whatsoever that he could have acquired the skills to do this. If there were really just 2 or 3 people in on the scheme (which is possible), at least one would have to be, IMO, no older than 45 to possess the necessary skills, and accordingly would have to have joined the scheme after it was already underway (though possibly as long as 15-20 years ago, when it was much smaller).
Alternatively, though, it is actually possible that someone hired to generate all this stuff, or at least to set up the porgramming to do it, didn’t know what it was for. I work in a related business and deal with some very high level hedge funds. They do have some brilliant, but highly compartmentalized “quant geeks” roaming around, who could be told to set up reverse-engineered trading data, ostensibly for the purpose of assembling data in order to develop a future trading strategy based on what *would have* worked if is had been done in the past. Then hand the data, along with faked starting capital accounts to: 1)a different quant geek with accounting-type expertise, and tell him this is the data on what actually happened, and that his job is to update the capital accounts; and 2) to yet another quant geek, with instructions to set up a program so that “in the future” similar trade data can be advance-fed into a system which will place trading orders and generate trade tickets. These geeks tend not to ask questions about how their tasks fit into the larger world — they love to bury themselves in their programming and spreadsheets, and let others deal with that confusing “people stuff”. If something along these lines happened, there had to be one mastermind who is extremely smart and quant/computer savvy, and is therefore not Bernie.
Whether there were only 2-3 really aware of the scheme (e.g. possibly Madoff, his wife, and the head of the pseudo-accounting firm that “audited” the Madoff advisory business), or a dozen or more, there were certainly quite a lot of other people — auditors, regulators, bankers, etc — who were shirking their duties to an appalling degree, just assuming everything was fine because it was “Bernie Madoff”, and confident that if anything was really amiss, somebody ELSE would have caught it and blown the whistle. When everybody who is supposed to be scrutinizing this sort of thing assumes they don’t really have to, because somebody else is also supposed to be doing it, a scammer can pull off almost anything. Bernie may have had a well above average awareness of the degree to which Wall Street/hedge funds are operating on the “I’m sure somebody else has checked it out” system, and along with one or more accomplices, exploited that awareness to a truly extraordinary degree.