Shares of cruise operators are suffering double-digit percentage selloffs Thursday to multi-year lows, as investor fears of the coronavirus outbreak intensify. Shares Royal Caribbean Cruises Ltd. RCL, -1.23% tumbled 16.6%, putting them on track for the lowest close since Sept. 19, 2016, and for the biggest one-day drop since Jan. 30, 2009. Carnival Corp.'s stock CCL, -1.33% dove 12.7%, and is headed for the biggest one-day drop since April 27, 2009 and for the lowest close since Aug. 17, 2009. Norwegian Cruise Line Holdings Ltd.'s shares NCLH, -1.37% dove 13.2%, which would be the biggest one-day decline since the company went public in January 2013, as they head toward the lowest close since June 24, 2013. Of the three, J.P. Morgan analyst Joseph Greff said Royal Caribbean, rated overweight, was the "best positioned" to weather the ongoing slowdown from a growth perspective, and subsequently "the best positioned to outperform coming out on the other side." Greff also rates Norwegian overweight, saying he sees "value for patient investors," while he rates Carnival neutral given his belief the company will "underperform faster growth peers coming out of this event." The cruise stocks' selloff comes amid a broad stock market selloff, in which the Dow Jones Industrial Average DJIA, -0.46% is shedding 791 points, or 2.9%.