As the Dukes discuss their wager, which means ruining Louis' life and raising Billy Ray to take his place, Randolph says "We've done it before. This time, it's in a good cause.". So how many lives have they previously shattered For the Lulz before this?
For clarity, the traders on the floor probably aren't using their own money, and their firms probably aren't, either.
If a firm used its clients money for its own trades and lost it, not only would the firm go bankrupt, but the people who authorized doing so would go to jail for securities fraud. And even if you make money doing that deal, you're risking getting busted for embezzlement. A conviction for embezzlement or securities fraud will not only put you behind bars for a few years, it will also get your assets seized and liquidated for restitution and get you blacklisted from ever working on Wall Street again. Therefore, anyone who got bankrupted because they played with clients' money during this stunt completely deserved it.
And for that matter, what about the rest of the Dukes' employees? Granted, most of them were like Louis before the movie started, but they didn't ruin lives. All they know is that the firm they are working for is closed, right in the middle of winter.
The company's assets, including the payroll, were probably auctioned off rather than liquidated.
So we have a poor chap trapped in a gorilla costume and shipped off to Africa (as another gorilla's lover, no less!). This is horrifying enough. Then you realize that he's stuck in that (likely very hot) suit with duct tape over his mouth - he can't eat, drink, or even call out for help. Unless he's lucky enough that someone notices something amiss with the "gorilla," he will likely die of dehydration during the boat ride!
One would think the costume likely isn't that durable, though that only leads to more bad implications should the large male gorilla uncover him...
During the final scene, after the Secretary of Agriculture gives out the real crop report, Louis and Billy Ray stop selling and wait for the price to bottom out before they start buying back the contracts they need. Billy Ray is treating it like a joke, but Louis appears a little more desperate. He knows that if they don't acquire the number of contracts to cover the ones they sold earlier, they will be in almost as much trouble as the Dukes are.
While it seemed that Billy Ray was treating the buying as a joke, he is being specific on who he buys from. He wants to make sure that Wilson—the Dukes' personal trader—was unable to unload his contracts, despite being in range of both Winthrope and Valentine.
Randolph and Mortimer Duke have portraits of then-President Ronald Reagan and former president Richard Nixon on their desks, respectively. Each represents the brothers' personalities. Neither one particularly cares about the lower class, but Randolph has a charming, kindly attitude (Reagan), whereas Mortimer is more upfront about his disdain (Nixon).