Many stock investors collect dividends. Hiroto Kiritani, however, collects melons. And ramen noodles, McDonald's hamburgers, the clothes on his back, anything, really, that Japanese companies send him, gratis, just for owning their stock.

Kiritani, 65, is a big-time player in an obscure corner of the Japanese investment world: "yutai," which loosely translated means "hospitality."

Yutai are gifts that a growing number of Japanese companies send to stockholders as a courtesy, a sort of thank you for owning their shares. While companies in other places occasionally throw perks at stockholders, the practice has reached its ultimate expression in Japan, where a cottage industry has sprung up around yutai.