Global X Social Media Index ETF (NasdaqGM: SOCL) managed to hold its head above water Monday despite a sharp decline in shares of Facebook (NasdaqGS: FB), the fund’s fifth-largest holding, on worries the stock is still overvalued.

Facebook shares were off more than 10% at one point Monday, triggering Nasdaq circuit breakers designed to prevent short sellers from piling on and driving the stock down further.

Facebook slipped 8% in afternoon trading while SOCL rose 0.8% at last check.

The stock accounts for 6% of the social media ETF’s portfolio. The fund, which was launched in November 2011, holds $15.3 million in assets.

Investors hammered Facebook shares after a Barron’s weekend story saying the stock may only be worth $15. “That would be roughly 24 times projected 2013 profit and six times estimated 2013 revenue of $6 billion, still no bargain price,” Barron’s said.

Facebook shares were trading just above $21 on Monday following the sell-off. The social network company’s stock is down more than 40% from the dismal IPO.

“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,” Morningstar says in an analyst report on the stock.

SOCL, the social media ETF, is up 5.7% year to date.

Global X Social Media Index ETF