Share buybacks are as American as mom, apple pie and hot dogs on the Fourth of July.

You’d never guess that given the many politicians on both the left and the right who say share repurchases are a newfangled, evil spawn of deregulation. Buybacks, argue their critics, barely existed before the Securities and Exchange Commission changed a rule in 1982 and unleashed a multi-trillion-dollar torrent—enriching fat-cat investors, starving workers and stunting the long-term prospects of the companies buying back all those shares.

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