The stock value of Coca-Cola plummeted as the entire U.S. stock market showed a similar trend on that day and is not related to Ronaldo's press meet.
However, Forbes reported that the entire U.S. market was down on June 14. At 9.40 a.m. EST, the Coca-Cola shares were trading lower at $55.26-down by 1.6 percent from the closing price of $56.16 on Friday, June 11. The shares saw a decline of $4 billion in stock worth between 9:30 a.m. and 9:45 a.m. EST. Ronaldo moved the Coca-Cola bottles at 9.45 a.m. EST after the stock had already fallen. In fact, the prices rose after the press event began and touched the low of $55.20 later in the day.
Further, Coca-Cola shares became "ex-dividend" on June 14, where the shareholders receive dividends on a pre-decided date. Therefore when dividends were paid out, the stock prices were automatically adjusted (to a lower number), and this date coincided with Ronaldo's press conference.
Although Ronaldo did move the Coca-Cola bottle and the company's share prices dropped that day, Ronaldo's action did not cause the drop. The viral narratives around it are incorrect.