The Giving Pledge turns 10: These billionaires pledged to give away half their wealth, but they soon ran into a problem

The Giving Pledge was heralded as a worthy goal when it was announced 10 years ago this week, but those good intentions have been outmatched by a mighty foe: the breakneck pace of wealth creation. Though they’ve promised to shed at least half of their wealth for the common good, many of the billionaires who have signed the Giving Pledge are richer than ever, the Institute for Policy Studies said; it added that, “while some pledgers earnestly intend to fulfill their promises, many are unable to because their assets are simply growing too fast.” The list of pledgers includes well-known business figures such as Tesla TSLA, -2.47% co-founder Elon Musk, Virgin SPCE, -5.63% Group founder Richard...