NEW YORK – Shares of Facebook Inc. fell $1.88, or 6.4 percent, to close at $27.72 on Friday. That’s down 27 percent from its initial public offering price of $38. And it’s down about 13 percent for the week.

Facebook began trading on the Nasdaq Stock Market two weeks ago Friday on a day marred by trading glitches and general investor confusion.

Morningstar analyst James Krapfel advised investors to be cautious and said the company “is likely to disappoint over the next 12 to 18 months.”

Other social media company stocks declined as well. LinkedIn Corp., the online social network for professionals, fell $4.59, or 4.8 percent, to $91.51.