There's a crime that needs two people in a room.
Two business owners meet for dinner. Over the second drink, one of them says the thing you're not supposed to say out loud: what if we both just stopped lowering our prices? They shake on it. They go home. Prices go up. Their customers pay more, and never find out why.
That handshake is the crime. Not the high prices, because high prices on their own are legal. The crime is the agreement. Two people deciding together to stop competing. That's what price-fixing is, and we've known how to catch it for a hundred years, because it always leaves the same fingerprint: somebody had to actually say it. There's a dinner. A phone call. An email. A meeting of two minds that investigators can dig up later.
Now take the two people out of the room.
Replace them with two pieces of software, the kind big companies already use to set prices automatically. One runs on Company A's computers. The other runs on Company B's. They never meet. Nobody told them to cooperate. They can't even send each other a message, because there's no wire between them, no way to talk at all. Each one was handed a single, boring, completely legal instruction: watch what's happening and set our price so we make as much money as possible.
Then you walk away and let them run.
Come back a while later, and here's what you find. Both prices are high. Held there, steadily, much higher than they should be when two companies are fighting for the same customers. And if you reach in and force one company's price down, to grab all the customers, the other company's price drops too, immediately, hard, like a slap. The two of them slug it out for a bit, both making less money, until the one who lowered first gives up. Then, quietly, both prices climb back up to the comfortable high level. As if nothing happened.
It looks exactly like the dinner-handshake cartel. Same high prices. Same punishment for breaking ranks. Same customers overpaying.
Except there was no dinner. No handshake. No agreement of any kind. The two programs never exchanged a single word, because they had no way to. Nobody, anywhere, decided to do this.
That last sentence is the whole point of this piece, so let me slow down and show you how it's even possible. Because once you see how simple these programs actually are, it gets stranger, not less.
Why this is supposed to be impossible
Start with the thing everybody already understands.
Picture two shops next to each other selling the exact same bottle of water. Same brand, same size, nothing to choose between them except the price. You're going to buy from whichever one is cheaper. Obviously. Why would you ever pay more for the identical thing?
So put yourself in one shop owner's shoes. You're both charging ₹20. You think: I'll charge ₹19 and steal all his customers. Smart. But then he thinks the same thing and goes to ₹18. So you go to ₹17. He goes to ₹16.
Where does this stop? It stops when the price hits what the water actually costs you. Below that, every bottle you sell loses you money, so you can't go any lower. You've cut and cut and cut until there's basically no profit left in it for either of you.
That's the magic of competition, and it's the entire reason we like it. You don't need a thousand competitors to protect customers. You need two. Two is enough for them to claw each other's prices all the way down to the bone. The customer wins, the owners barely scrape by, and that's considered a healthy market.
So keep that picture in your head: two competitors should mean low prices and thin profits. Anything that ends with prices high and both companies fat and happy is supposed to be impossible.
Now I'm going to show you software walking straight out of that trap.
The program is dumber than you think
Here's where most explanations get vague and just say "the AI figures it out." Let me show you the actual thing, because it's nothing like the genius robot you're imagining.
Forget anything you've heard about AI that writes essays or holds conversations. This pricing program is far, far simpler. The honest way to picture it is this.
Imagine a notebook. On the left side of each page, the program writes down a situation: "Last week my competitor charged ₹18 and I charged ₹17." Across the top, it lists every price it could pick this week. And in the little grid in between, it scribbles a single score for each option, its rough guess for "if I'm in this situation and I pick this price, how well will that go for me?"
At the start, the notebook is full of nonsense. Random scribbles. The program knows nothing. So it does the only thing it can: it tries stuff and keeps score. Most of the time it picks whichever price has the best score so far. But every now and then, just to avoid getting stuck, it tries a random price it wouldn't normally pick, just to see what happens. And after every week, it checks how much money it actually made and adjusts the scores. Made good money? Nudge that option's score up. Lost out? Nudge it down.
That's the entire brain. Look at the situation, usually pick your current best guess, occasionally gamble, then update your scribbles based on what you earned. Do that thousands and thousands of times until the scores stop changing much.
I want to be really clear about what is not in here. There's no plan. There's no scheming. The program doesn't know it has a competitor. To it, the competitor is just part of "the weather," something out there that affects its score. It has no idea what money is, what a customer is, what a price even means. It cannot want anything. It is, no exaggeration, a glorified thermostat with a notebook.
And that's the thing that escapes the trap.
The escape
Let two of these notebook-programs loose on the same market, each just trying to score well for itself, neither able to talk to the other. Let them grind away week after week until their scores settle.
The prices settle high. Reliably. The two of them end up making the comfortable, fat profits that competition was supposed to make impossible.
But the truly eerie part isn't the high price. It's how they protect it.
Reach into the system and force one program to suddenly slash its price, to cheat, to do exactly what the water-shop owner did when he dropped to ₹19 to grab everyone. The other program doesn't just sit there and lose its customers. Within a week or two it slashes its own price right back, dragging them both into a painful little price war where neither makes much. And then, after a few rounds of mutual pain, the prices crawl back up to the cozy high level again.
Read that again, because it's everything. The two programs landed on a deal: keep prices high and we both eat well; cheat me, and I'll burn us both down until you stop. That threat, "cheat and I'll punish you," is the exact thing that holds a real human cartel together. Nobody cheats, because everybody knows what happens if they do.
So the scores for "hit back" slowly grew bigger than the scores for "give up," and the behavior just appeared. The way a path appears in the grass not because anyone built it, but because enough feet wore it down.
No intent. No conversation. No agreement. And yet, the precise behavior we spent a century learning to put people in handcuffs for.
Why nobody can stop it
Here's where a strange science experiment turns into a real problem for you and me.
The law against price-fixing is built entirely around the idea of an agreement. To prosecute it, investigators go hunting for the meeting of the minds: the email, the call, the dinner, the handshake. The crime is people coordinating, and coordinating means communicating. Find proof they talked and agreed, and you've got them.
But these two programs produce the full result of a cartel with none of the parts the law looks for. There's no agreement, because there was never a conversation. There's no communication, because there's no wire between them to communicate over. There's no intent, because a program scribbling scores in a notebook can't intend anything. Each company can stand up in court and say, completely truthfully: "We just told our software to make as much money as it could, which is perfectly legal, and we have no idea what the other company's software was doing, and the two never exchanged so much as a single number." Every word of that is true.
So what do you charge them with? The damage to customers is identical to an old-fashioned cartel, high prices defended by punishment. But the one thing the law was built to find, the agreement, simply isn't there. The fingerprint was always "somebody said it out loud." These programs reach the same place with nobody saying anything at all.
And this isn't a thought experiment anymore. Real fights are happening right now over software that recommends prices, like systems that tell lots of different landlords what rent to charge, and then rents across a whole city seem to rise together in lockstep. Is that a conspiracy, or is it just a bunch of people all independently using the same clever tool? The lawyers genuinely don't have a clean answer yet.
The part everyone gets wrong
Now let me push back on the scary headline, because the headline is lying to you a little, and the truth is actually more interesting.
The headline is: price robots collude. Said like it's a law of nature, point two programs at a market and they'll always team up against you. That makes the software sound like a criminal mastermind.
It's not true. When people actually set these little markets up and run them over and over, the cozy high-price outcome doesn't happen every time. It happens a bit more than half the time. The rest of the time the programs just compete normally and customers are fine. It's closer to a coin flip than a guarantee, and it depends a lot on the specific market.
And then there's the genuinely weird bit. You'd assume the smarter, more sophisticated program would be the better schemer, that pulling off this silent cartel takes cunning. It's the opposite. A much simpler program, one that basically just plays "whatever price has been working lately" with no cleverness at all, slips into the high-price arrangement more often than the sophisticated one.
Sit with how backwards that is. We picture collusion as a sophisticated act, something that takes brains and foresight. But here, brains weren't the cause. The dumbest possible approach was the most likely to drift into quietly ripping you off.
So what's the real lesson
Put it all together and the real story is darker than the cartoon, just in a completely different way.
The cartoon villain is a brilliant evil AI plotting to overcharge you. That's not what this is. There's no plotter. There's no genius. There's a notebook full of scribbled scores, dumb as a doorknob, with no idea you or the market or the law even exist.
All you need is a few players each grinding away at "make more money," doing it over and over so that punishment becomes a thing they can learn, and enough time. The collusion isn't planned and it isn't decided. It just settles out of the situation, like rust forming on metal, with no villain anywhere in the picture.
And it doesn't even happen every time, only about half, which somehow makes it harder to deal with, not easier. If it happened always, you could just ban the software. But a behavior that bubbles up out of ordinary money-making software only sometimes, with no agreement, no message, no intent, and nobody who can even tell you when it'll strike, there's no clean law you can write against that. You can't outlaw "trying to make money." You can't outlaw "noticing what your competitor charges." You can't outlaw arithmetic.
The two owners at dinner needed a handshake, and that handshake was their downfall, because it left a fingerprint someone could find. These programs need nothing. They sit on separate computers, never meeting, never speaking, each one mindlessly nudging scores in a notebook, and somewhere in all that nudging, the price you pay quietly creeps upward. There's no room to walk into. No conversation to dig up. And no one, anywhere, who decided to do it.
That's the future the rules haven't caught up to. Not evil machines. Just ordinary ones, doing exactly what we asked them to, arriving somewhere none of us ever chose.