This week, the so-called meme stock trading started to be active, and people were talking about the possibility of a short squeeze.

As retail traders locked in their latest favorites on Wednesday, another batch of names was added to the meme stock frenzy.

As of 2:32 pm New York time, prison operator GEO Group Inc. soared 60%, and Clean Energy Fuels Corp. rose 24%, replacing companies such as ContextLogic Inc. and Clover Health Investments Corp. that led the gains on Tuesday. In Europe, Air Berlin rose by 138% after soaring 54% the day before. At the same time, after Northcoast and Stifel downgraded their stock ratings from buy to hold equivalent recommendations, the fast food chain Wendy’s stock reversed its rise from Tuesday.

This week, so-called meme stock trading began to heat up, as investors on the forum opposed short sellers, WallStreetBets and other social media platforms were talking about possible shorts.

For most of the past month, there has been no change in the broader stock market, so the speculative frenzy between Reddit’s favorite names has been especially pronounced. Although the share prices of AMC Entertainment Holdings Inc. and Clover Health rose at least 85% in June, the Russell 3000 Index rose only 1%.

Matt Maley, chief market strategist at Miller Tabak + Co, said: “The Meme stock boom is a liquidity phenomenon. This is far more than just what Reddit traders are participating in. There are many momentum-based hedge funds ( (Algorithms) There is a lot of money to promote these things.”

Due to the recent boom in some meme stocks, the trading volume of options has increased. Barclays analyst Maneesh Deshpande said in a report that the daily trading volume of single stock options increased to approximately $383 billion in the past week.

Deshpande said in the report: “One of the surprising developments in the past week is that as retail options activity increases and upward demand for meme stocks increases, the single-stock tilt (in other parts of the universe) has become steeper. “

On Wednesday, the chairman of the US Securities and Exchange Commission Gary Gensler called on the agency to review the structure of the stock market, including so-called best execution requirements. Prior to this, the US Securities and Exchange Commission said earlier this week that as meme stock continues to soar, it is reviewing the market for signs of manipulation.

GameStop Corp. started a meme boom in January and announced its first quarter results after the market closed today. At the video game retailer’s annual meeting this morning, newly elected chairman Ryan Cohen yelled at the retail traders who pushed the stock market up. “We are fortunate to have such a special group of investors holding the company’s stock,” he said.

Wendy’s rating was downgraded from Stifel’s buy to hold, and the company stated that the stock’s valuation now fully reflects its assumed growth to reach its target price of $25. Analyst Chris O’Cull said in a report that he is still “constructive to the company’s fundamental outlook.”

According to the data of IHS Markit Ltd. as of 2:32 pm in New York, other stocks that have changed today and short interest accounted for the percentage of liquidity:

• Atomera Inc holds a 12% short interest, up 22% on Wednesday
• Clovis Oncology Inc. holds a 34% short interest, soaring 14% today
• Genius Brands International Inc. increased by 13%, short interest was 13%
• Inovio Pharmaceuticals Inc. rose 16% on Wednesday and holds a 26% short interest
• Invesco Mortgage Capital Inc. rose 19% on Wednesday, with a short interest of 12%
• PubMatic Inc. holds a 47% short interest, soaring 10% today
• Root Inc. holds a 14% short interest and rose 23% on Wednesday
• SmileDirectClub Inc. rose 10%, short equity was 18%
• World Wrestling Entertainment Inc. increases its holdings by 11% and short interest is 23%
• Ziopharm Oncology Inc. holds a 14% short interest and rises 13%