Pump and dump cryptocurrency schemes are alive and well in 2018.

Researchers from Oklahoma, New Mexico, and Israel looked at Telegram and Discord channels to locate what they termed “pump signals” in their report. Between January and July this year, the researchers found 3,767 such signals on Telegram and 1,051 on Discord. These efforts spanned more than 300 different cryptocurrencies.

To enact a pump and dump, multiple people artificially inflate the price of a stock (or, in this case, a cryptocurrency) by generating a lot of hype and buying up a bunch of it at once. When that succeeds in driving up the price, the people who “pumped” will sell their stock/cryptocurrency to make a profit, leaving the people who were duped into buying with nearly worthless holdings. If you’ve seen The Wolf of Wall Street, then you know what a pump and dump looks like—and that it’s illegal.

While not all of efforts the researchers looked at were successful, those that were had a significant effect on cryptocurrency prices. Ten percent of the pumps on Telegram increased the price of a coin by more than 18 percent in a matter of five minutes. On Discord, 10 percent of the schemes were able to raise the price of a coin by 12 percent in five minutes.

Related: How Should We Fight Crypto Scammers?

Ultimately, the coin’s ranking was a big part in determining the success of the pump. The lower they ranked on Coinmarketcap, the more pumpers were able to increase the coins’ price, likely because fewer people already had stake in those markets. People who participated in the pump (either unwittingly or not) were able to make a more significant splash.

A lot of these pump and dump schemers aren’t shy about what they’re doing. Multiple pump and dump channels on both Telegram and Discord used the words “pump” and “dump” to openly describe their motives. These channels would alert others to the scheme a day or two before the pump was set to commence, releasing the name of the coin they’d be targeting immediately prior to act.

These types of pumpers did indulge in a single subtlety. Instead of posting the name of the coin they’d be targeting, they often posted an image. This would make it harder for people searching in the social apps for the offending coin name to find the group’s plans.

Other pump and dump channels were more guarded about their schemes. They’d try to avoid explicitly referring to “pumping and dumping” and wouldn’t announce their pump plans ahead of time. Rather, they posted only the name of the coin they’d be targeting and its price right as the pumping was to start.

Neil Gandal, one of the study’s authors and an economics professor at the Berglas School of Economics in Israel, got interested in cryptocurrency pump and dumps after authoring a different research paper about bitcoin price manipulation. “At the end of that paper, we wrote that that thinly traded, unregulated cryptocurrency markets likely remain vulnerable to manipulation today,” he wrote to BREAKER in an email. “Hence, it was only natural to examine pump and dump schemes, which are another form of price manipulation.”