In financial markets, the Hong Kong dollar is known as a “widow-maker”, a ruinous trade that inflicts painful losses on successive generations of investors. While betting against Japanese government bonds has been the most notorious widow-maker trade, challenges to Hong Kong’s currency peg to the US dollar date back to the 1997-98 Asian financial crisis and continue to attract speculators even though the trade has yet to pay off. As recently as May 5, the Hong Kong dollar – which has been pegged...