It’s enough to make you wish for a blockchain.
Bloomberg, 17 February 2017
Oops! Somehow shareholders owned 33 percent more Dole Food shares than there were Dole Food shares.
People owned more Dole shares than actually existed, because they bought them from short sellers, and now if you want to pay off all the owners, you have to track down the short sellers to make them pay up. That problem is hard, and it seems like the current system might have real problems with it: If the short sellers died, or went out of business, or closed their accounts, or just really don’t want to pay some extra merger consideration three years after the fact and yell a lot when their brokers ask them to, then the brokers will have a hard time finding all the money.