In the present moment pump and dump is a buzz word in the block chain cryptocurrency market. Because main reasons are the unpredictable volume of BTC and XRP. A few months back BTC started has pumped and XRP has started falling down. If there was a pump and dump group then it would be better for crypto lover.
When I see pump and dump firsr what comes to my mind is some low volume token not btc eth or some other. Bigger cryptocurrencies depend from a lot of factors. Most of them are about daily news, new president, new regulation, pandemic etc. Its not just simple pump and dump theory.