It is the investor equivalent of the cash-for-clunkers scheme. Shares in Japan's mostly lossmaking carmakers continue to outpace the broader Tokyo stock market. The big three have risen by between 40 and 120 per cent this year. Nissan Motor, Japan's third-biggest manufacturer and, in stock price terms, last year's dog, has out-performed even the Shanghai bourse.

Investors have pushed down on the accelerator mostly because of various government schemes. US car sales rose by about 16 per cent month on month in June, largely thanks to the cash-for-clunkers programme, with fuel-efficient Japanese cars leading the pack.

According to US transport data, Toyota Motor – the biggest global carmaker by sales – accounted for three of the top 10 models bought under the scheme. Meanwhile, sales incentives launched in China, the world's biggest market, have sparked a mini-boom. Honda Motor, Japan's second-biggest carmaker, lifted its projection for sales in China by 8 per cent to 840,000 this fiscal year.