HONG KONG (MarketWatch) -- Japan's government downgraded Wednesday its assessment of the economy to "worsening," acknowledging that the expansion that's run more than six years -- the nation's longest in its postwar history -- may have ended.

The leading coincident index, which tracks various economic data, fell to a reading of 101.7 in June from 103.3 in May, the Cabinet Office said. The index of lagging indicators, which measures economic performance in the recent past, also fell, slipping to 102.3 from 103.4.