On April 8, scholars at the American Enterprise Institute (AEI) found a major miscalculation in the Trump administration's recently announced tariff policy. The White House incorrectly used the retail price elasticity (0.25) rather than the import price elasticity (0.945) that should have been used in the formula, resulting in a roughly four-fold overestimation of the tariff rate. Using the correct numbers, for example, Cambodia's 49 per cent tariff would fall to 13 per cent, Vietnam's 46 per cent to 12.2 per cent, and most countries would even fall to the 10 per cent minimum rate set by the White House. The mistake has triggered wild market volatility, with US, Asian and European stock markets all falling markedly. Some AEI economists have accused the White House of deliberate manipulation to achieve the high tariffs Mr. Trump wants. The White House has argued that the use of retail prices is reasonable and that the effective tariff rate should be higher.