Because it's so much work to be a Mormon in good standing, Mormons tend to trust other Mormons, making them famously vulnerable to large scams operated by the small number of conmen self-disciplined enough to have spent years piling up credentials as good Mormons.
Bernie Madoff's $50 billion Ponzi scheme was rather like the kind of "affinity scams" that have plagued Mormons. Madoff joined all the right Jewish country clubs and gave to all the right Jewish charities, allowing him to fleece some very deep Jewish pockets.
But the sophistication level of the victims is rather different. While there are rich Mormons, overall Mormons are pretty middling in wealth (depending on whether you measure per capita or per family), while Madoff's victims weren't middling.
Why did members of the Palm Beach Country Club, various hedge fund managers, and major league sports franchise owners fall for what appears to have been a simple, old-fashioned scam in which implausible returns are seemingly delivered, but only by using new investors' cash to pay off old investors? (By the way, the golf scores Bernie reported to the USGA for handicapping were all in the eighties, as remarkably consistent as his reported return on investment.)
One theory (and it's only a theory) is that more than a few of these sophisticated clients assumed Bernie was cheating -- either through insider trading or "front-running" -- and they wanted in on his illicit profits.
They just never dreamed Bernie was cheating them.