Facebook is on a hot streak.
Shares of the social giant are up more than 6 percent in the past five trading sessions alone and have risen more than 40 percent on the year.
"Facebook's out performance is notable in a year where many large cap internet stocks like Google, eBay, Twitter and Amazon are down," said Riskreversal.com's Dan Nathan Monday on CNBC's "Fast Money." Google, eBay, Twitter and Amazon are down 4 percent, 8 percent, 19 percent and 21 percent, respectively, year to date.
But according to Nathan, some traders feel the run in Facebook may have gotten a little long in the tooth. On Monday, in a trade that caught the attention of many options traders, one investor bought 6,500 Oct. 24 weekly 75-strike puts for 80 cents. The trader is basically betting a half a million dollars that Facebook shares will be below $74.20 by this Friday, or down about 5 percent from current levels. A put gives investors the right to sell a stock at a set time and set price.
"What's curious about this trade is that there is no event this week other than market trading," Nathan added. "This trade was likely very short-term protection for someone looking to stop out a long for the week."
Facebook is set to report third-quarter earnings Oct. 28 after the bell.