depends on your definition of predicting a market
do you need trades with price points either side or calling bottom and tops or calling timeframes for price directions

if you want an example of the ability to analysis and predict markets.

My Bitcoin Profit From BTC/USD trades for 2017/2018 most of which were posted on steem if you need some verification

2017 + 400%
2018 + 780%

yes i wholly believe big data trading corps would utilize the trading data they buy from millions of users to front run markets short sell pump and dump etc

Robinhood has over 4 million users
https://www.investors.com/news/robinhood-app-has-more-customers-than-online-broker-etrade/

Article with details on Robinhood selling User Data to HFT firm
https://bitcoinist.com/no-such-thing-as-a-free-lunch-robinhood-user-info-sold/