An index launched a year ago to give investors greater exposure to China’s internet giants is now the world’s worst-performing major technology gauge.

The Hang Seng Tech Index has been on a roller-coaster ride in the last 12 months. The gauge, which marks its one-year anniversary on Tuesday, was up 59% at its February peak but has since seen more than $551 billion in market value wiped out amid Beijing’s clampdown on the sector.

That has reduced the gain to nearly 6%, compared to more than 40% for the MSCI World Information Technology Index and the Nasdaq-100 Index. The measure also lags onshore peers: the ChiNext Index is up 35% in the period.