EPR, SAFETY, LIQUIDITY, RETURN Billionaires Elon Musk and Mark Zuckerberg used mortgages to buy multimillion-dollar mansions. Here’s why that’s a savvy financial decision | FortuneSource: FortuneBillionaires Elon Musk and Mark Zuckerberg used mortgages to buy multimillion-dollar mansions. Here’s why that’s a savvy financial decision | Fortune