Tanaka Kikinzoku Kogyo K.K., Japan's biggest bullion retailer, said sales of platinum bars to local investors more than tripled in the first quarter from a year earlier as lower prices boosted demand.

Sales volumes in the three months to March 31 jumped 217 percent as yen-based prices for platinum bars slumped 51 percent to ¥3,170 a gram ($996 an ounce) on average in the first quarter from a year earlier, the company said Thursday. "Platinum sales surged as prices became affordable," the statement said. Tanaka does not disclose sales volumes.

Tanaka's purchases of platinum bars plunged 49 percent compared with January to March last year, when investors sold the metal to take advantage of a rally in prices to a record. Tanaka's sales volumes of platinum bars in Japan were 3.7 times more than total purchases.

Tanaka's sales of gold bars rose 40 percent in the first quarter from a year earlier.