Elon Musk on Wednesday became the first person to surpass $500 billion in net worth, powered by a rebound in Tesla's share price this year and swelling valuations of his other tech ventures.The milestone comes just under a year after Musk's net worth crossed $400 billion and underscores his lead as the world's richest person.Musk's fortune briefly hit $500 billion on Wednesday, before settling at $499.1 billion at 5 p.m. ET, according to Forbes' billionaires index.His wealth is tied closely to