The company more than halved its net profit forecast for the fiscal year through March to 40 billion yen (US$409 million) from the 85 billion yen it projected in May.

It also slashed its revenue outlook by 11 percent to 1.65 trillion yen (US$16.9 billion) and now expects operating profit to fall by 43 percent to 60 billion yen (US$613 million).

The Tokyo-based company blamed the earnings downgrade, announced late Wednesday after the stock market had closed, on declining demand for domestic trucks, higher prices for raw materials and an appreciating yen.

The shares fell 19.2 percent to 164 yen in late afternoon trading on the Tokyo Stock Exchange, far worse than the benchmark Nikkei 225 stock average's 6.5 percent decline.