Carnival Corp. CCL, -7.04% said Monday morning that it may sell up to $500 million in stock from time to time as part of an at-the-money equity offering program. The cruise company would use the proceeds from this stock offering to purchase ordinary shares of Carnival plc and may use any remaining proceeds for general corporate purposes. Carnival said in a filing with the Securities and Exchange Commission that it would sell shares through the offering only when shares of Carnival plc in the U.K. were trading at a discount to Carnival Corp.'s common stock. The announcement comes after Carnival disclosed last week that it expects a $2.1 billion net loss for the second quarter on a GAAP basis and that 42 ships from eight of the company's brands had either resumed operations or were planning to by Nov. 30. Shares are down 4.8% in Monday morning trading. They've gained 70% over the past 12 months as the S&P 500 SPX, +0.23% has risen 42%.