When shopping in Japan, a phrase you'll hear all the time is "Do you have a point card?" And the most common is the T-card, which can be used at hundreds of thousands of shops nationwide, from car accessory dealers to convenience stores.

Half of Japan uses a T-card regularly, and the system records purchases to the value of about ¥7 trillion ($63 billion) annually according to operator CCC Marketing. That's a massive amount of data on who's buying what — and now for stock pickers it's a new source of information on which companies' sales are rising or falling.

CCC has teamed up with big-data company Nowcast to analyze the T-point data and provide sales forecasts for about 50 companies that manufacture consumer goods, ranging from toiletries to digital cameras. Nowcast said it will start in April, but declined to name any of the companies yet.