Yes that’s what I meant, I thought to myself I would learn about all that stuff when I first watched the movie as a kid.
The commodities markets are a magical wonderland of futures contracts, short sells, long buys, and successes that elude the average investor.
Hillary Clinton famously made a killing in cattle futures, after having no experience in the market prior. The only thing she had going for her at that time was being First Lady. Lots of speculation on her using insider information to illegally profit from that investment. But, like we've always seen, she wears Teflon grandma panties.
The movie doesn't show a realistic trading scenario. Trying to make any sense from it by learning how commodities trading works would just confuse you more.
Let's just say that the trading would not have started so late in the morning, only to end a short time after the crop report was announced. What we are to believe is that the Dukes were buying up all the FCOJ futures contracts at any price to make a profit when the report announced a horrible orange crop harvest (low supply = higher prices).
You have to make a lot of assumptions for this scenario to even work. First, Winthorpe and Valentine (W&V) must have shorted the shares they were selling at the start of trading. That means they promised to repay the share's owners a stated price above current market value say a month in the future. When the prices plummeted after the report was aired, they then repurchased the shares they owe to the short seller, meaning they can replace the borrowed shares they just sold for a profit with cheaper shares. They made money both as the price rose and again as it fell.
Without inside information, commodities trading is a scary business. W&V had that information, but then passed along disinformation to ruin the Dukes.