How much can retail really influence a stock's momentum?

My question is simply can retail buyers unintentionally maintain downward momentum buying share at a perceived discount if a stock has sufficient share to borrow? If so, would a sharp drop off in buying slow or potentially reverse the momentum-driven portion of a price drop.

For background: Watching AMC over the last week, and a question or discussion of this nature is not going to get a realistic or coherent response in their subreddit, so I thought this would be a good place to broaden my financial knowledge.

There were the more clear-cut technical reasons for the price drop including two reverse splits, a share conversion, share dividend issuance, and potential new share issuance (the last two possibly making up ~20% of the shares outstanding). There was substantial trading and decline leading up to it, which could be chalked up to expected dilution being priced in, positions closing out ahead of the split, and just normal profit making on volatility. $AMC Entertainment (AMC.US)$ $NVIDIA (NVDA.US)$