Facebook (NasdaqGS: FB) joined the social media exchange traded fund on Thursday as the third-largest stock holding with an 8.8% portfolio weight.

The stock was added to the tracking benchmark, the Solactive Social Media Index, after five days of trading.

Global X Social Media Index ETF (NasdaqGM: SOCL) holds assets of about $25 million and trading volume in the fund spiked last Friday when Facebook went public. SOCL charges net annual operating expenses of 0.65%.

The ETF’s top holding is LinkedIn (NYSEArca: LNKD), which went public last year, at 10.2% of the portfolio. [FOX Interview: Tom Lydon Says Facebook to Join These ETFs]

SOCL has taken a hit on the disappointing Facebook IPO and is down more than 10% for the trailing month.