If this is accurate, it finally explains something I've been asking about for years: The loan is paid back after the step-up in basis. That's the loophole. If the loan was paid back before step-up, the estate would still have to pay capital gains tax.
The step-up in cost basis on death is the original sin that underpins the entire debate over unrealized gains. It's disheartening to see so much thought and deliberation going into an obviously toxic idea (taxing unrealized gains) when the obvious solution (removing the cost basis step-up when assets change hands) is being ignored. Inherited wealth is the least earned, so it should be politically palatable to change…
Taxing unrealized gains in general I think is impractical since many assets simply don't have well-defined valuations, but if you take out, say, a $10 million loan using, say, shares in a privately traded company, then those shares are apparently worth $10 million dollars because the owner and the bank agreed they were.