The nation's negative interest rates are boosting demand for gold, according to its biggest bullion retailer.

International prices have rallied 18 percent this year as investors seek a haven from financial market turmoil. For individual investors, the Bank of Japan's surprise move in January is adding to gold's allure, according to Takahiro Ito, chief manager at Tanaka Kikinzoku Kogyo K.K.'s store in Tokyo's Ginza shopping district. That's helped lift retail prices to their highest since July.

"Many customers are wagering that it's better to turn their savings to gold as a safe asset rather than deposit money at banks that offer low interest rates," he said in a phone interview last week.