Check out the companies making the biggest moves in premarket trading:

GameStop — Shares plummeted nearly 21% in premarket trading. The company announced Wednesday the ousting of chief executive Matthew Furlong and said Ryan Cohen would take over as executive chairman.

Wynn Resorts, Las Vegas Sands — The casino operators both shed about 2% following a downgrade by Jeffries to hold from buy. The Wall Street firm said Macao’s recovery is already priced into the stocks.

Signet Jewelers — Shares tumbled nearly 11% after the jeweler provided second-quarter revenue and operating-income guidance that fell short of expectations. Signet also lowered its full-year earnings and revenue guidance to below expectations, citing increasing macro-economic pressures on consumers and a softer-than-expected Mother’s Day.

Lucid — Shares advanced about 2% after Lucid’s head of China operations Zhu Jiang said the electric vehicle maker is preparing to enter the Chinese market. Reuters, citing a person familiar with the matter, additionally reported the company is considering setting up production in China.

T-Mobile — Shares of the wireless provider added about 1% in premarket trading after Wolfe Research upgraded T-Mobile to outperform from peer perform. The investment firm said T-Mobile’s stock could rise more than 20% after underperforming year-to-date.

Adobe — The stock gained about 2% following the company’s announcement it will offer its artificial intelligence tool, Firefly, to large business customers. Firefly is available through the standalone Firefly app, Adobe Express and Creative Cloud.

HashiCorp – The stock sank more than 22%, a day after the company reported a first-quarter earnings miss and revenue beat. HashiCorp also announced targeted spending cuts and an 8% workforce reduction, citing the current customer and economic environment.

—CNBC’s Jesse Pound, Sarah Min and Brian Evans contributed reporting.