Shares of Carnival Corp. /zigman2/quotes/202325446/composite CCL -5.82% shot up 5.8% to $19.57 in afternoon trading on heavy volume, as the cruise operator briefly flirted with a bull-market bounce off last week's 13-month low. Trading volume swelled to 57.1 million shares, enough to make the cruise operator's stock the most actively traded on the NYSE, and compared with the full-day average of about 39.4 million shares. The stock ran up as much as 8.3% to an intraday higher of $20.04 earlier in the session before paring gains. At that high, the stock had soared 22.3% since closing Dec. 1 at $16.38, which was the lowest closing price since Nov. 13, 2020. Many on Wall Street believe a bull market is defined by a rally of 20% or more on a closing basis off a bear-market low. The stock would have to close above $19.66 to make the bull market on those terms "official." Among other cruise operators, shares of Norwegian Cruise Line Holdings Ltd. /zigman2/quotes/204183397/composite NCLH -5.16% jumped 8.2% to trade 22.4% above its Dec. 1 13-month low of $17.79 and Royal Caribbean Corp. /zigman2/quotes/208854639/composite RCL -6.34% hiked up 4.9% to trade 16.9% above its Dec. 1 13-month closing low of $64.27. Meanwhile, the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.54% has gained 4.0% off its Dec. 1, seven-week closing low.