Individual investors looking for places to invest their money are getting dragged into shady schemes that persuade them to buy unlisted stocks with the promise of getting high returns once they get listed.

One woman in her 50s in Tokyo received a phone call in October in which the caller tried to persuade her to buy unlisted stocks. She was uncertain how the caller got her name and number, but asked the person to send her the materials.

She received a flashy pamphlet that said: "You can surely earn. It's like discovering a vein of gold."