After the price of herbs enters an upward trajectory, a situation arises where sellers don't want to sell. They hoard the herbs they have and wait for the price to increase before selling. Speculators also follow Nie Yan, buying herbs and waiting for the prices to surge, causing the price to soar even higher, so Nie Yan no longer needs to invest more money.
When something seemed off in the herb market, Qin Han immediately noticed the issue. In order to block Asskickers United, he rallied various major guilds under the Morey Consortium to gather herbs and dumped all their inventories onto the market. His selling indeed caused some problems for Nie Yan, causing the market price of herbs to momentarily revert to its original level. But after burning through nearly eight to nine million gold coins, Nie Yan managed to hold on and drive the prices back up. Many speculators in the market saw the prices have a tendency to soar, and they also stepped in, purchasing some in the process.