A social media ETF that counts Facebook (NasdaqGS: FB) as its third-largest holding is down 16% the past month amid the fallout of the IPO bomb.

Global X Social Media Index ETF (NasdaqGM: SOCL) has 7.8% of its portfolio in Facebook. The ETF is relatively small with about $18 million in assets.

Facebook shares have tumbled to below $27 after hitting a high of $45 in the IPO on questions over the company’s profitability and ad-driven revenue.

“Facebook is building the foundation to revolutionize online advertising. However, lack of near-term visibility and cloudy advertising metrics may temporarily stall revenue and profit growth,” says Morningstar analyst Rick Summer in a note.

“People spend more time on Facebook than any website on the Internet. By collecting information about users, their social connections, and their activities on the Internet, Facebook has a lucrative database that is highly valuable to advertisers,” he added. Still many of the company’s advertisers “are unsure if they are spending money wisely on Facebook ads today.”