Meme stocks GameStop and AMC tumble Tuesday on heavy trading volume

Meme stocks tumbled on Tuesday with huge trading activity in the shares.

GameStop dropped more than 9% with more than 6 million shares traded through 10:15 a.m. ET, already more than its 30-day average full-day volume of 4.6 million.

AMC Entertainment shares lost 3% with 76 million shares traded, already more than its 30-day average of 51 million.

The reason for the moves were not immediately clear, but both stocks are up big this month amid a broader comeback rally on Wall Street so some investors could be using that pop to take profits in the volatile shares.

There were some large block trades of GameStop in early trading on the NYSE. Outside of the open there were two trades of more than 20,000 shares apiece, according to FactSet data.

The NYSE briefly halted both stocks for volatility shortly after the open as the stocks popped then dropped.

The duo just notched a strong week as loyal retail investors kept pushing up the shares. GameStop shares rallied a whopping 67% last week as traders got a vote of confidence when chairman Ryan Cohen bought additional 100,000 shares of the video game retailer.

Meanwhile, AMC saw a 28% gain last week after the movie theater chain revealed its plan to buy a tiny gold miner. However, the move to take a significant stake in the gold miner with a shaky financial history confused many Wall Street strategists.

This is a developing story. Check back for updates.