For well over a century, US law has followed this basic template: Ban those backroom deals, and fair prices should be maintained. Across broad swaths of the economy, sellers increasingly rely on computer programs called learning algorithms, which repeatedly adjust prices in response to new data about the state of the market. These are often much simpler than the “deep learning” algorithms that power modern artificial intelligence, but they can still be prone to unexpected behavior. So how can regulators ensure that algorithms set fair prices? So if you want to guarantee fair prices, why not just require sellers to use algorithms that are inherently incapable of expressing threats?