Japan Exchange Group Inc., the main bourse operator in the world's second-largest equity market, tumbled in afternoon trading after forecasting full-year profit that missed analyst estimates.

Net income for the year through March 2015 will be ¥21 billion ($206 million), JPX said Monday, 35 percent short of the ¥32.5 billion average estimate of nine analysts surveyed by Bloomberg. Profit for the year ended March 31 was ¥29.8 billion, compared with the exchange's projection of ¥29.5 billion and analysts' prediction of ¥30.6 billion.

Japan Exchange shares dropped 6.23 percent at the close in Tokyo, while the Topix index slid 0.79 percent.