Billionaires Elon Musk and Mark Zuckerberg used mortgages to buy multimillion-dollar mansions. Here’s why that’s a savvy financial decision

Even the world’s most affluent people sometimes need a mortgage.

Elon Musk is the world’s richest man, on track to become the first-ever trillionaire, but he’s done one thing most average Americans have to do: take out a mortgage. 

The Tesla CEO has taken out several mega mortgages, including $61 million from Morgan Stanley, on five properties in California, according to the Los Angeles Times. That’s barely a drop in the bucket of his now $662 billion net worth, so it could...