Snap Chief Executive Evan Spiegel and his wife, supermodel Miranda Kerr, have helped pay off $550 million in medical debt for more than 261,000 Californians. The couple made a multimillion-dollar donation to Undue Medical Debt, a nonprofit that provides debt relief to people in financial need. The organization acquires medical debt in bulk from hospitals, physician groups, collection agencies and other groups for a fraction of the cost. "When someone you love is sick. All you want to do is focus on helping them get better," said Kerr, who is also the founder of skincare company KORA Organics, in a...