Halfway through Japan’s reporting season, companies are mostly hitting their marks, but some high-profile cautious outlooks from blue chips like Toyota Motor Corp. risk sapping optimism for the rest of the financial year.

Almost 60% of firms have beaten earnings estimates in the latest quarterly reports, with technology and consumer discretionary firms doing best and health care and financial companies lagging, according to data compiled by Bloomberg. But some investors are worried the earnings recovery could soon unravel as companies such as Toyota struggle to deal with high raw material costs and supply disruptions.

The world’s biggest automaker forecasts a 20% decline in operating profit for the current fiscal year despite posting robust annual car sales, citing an "unprecedented” rise in costs for logistics and materials. That even Toyota, known for its meticulous cost-cutting, sees higher expenses far outweighing the benefits of a cheaper yen spells trouble for many other Japanese manufacturers.