The "AI analytics" companies are all communicating expressly their intent when they purchase the data at the outset. This makes it legal.

Full disclosure, I'm a privacy advocate and believe this sort of selling of customer data should not even be allowed. That said, what the companies you allude to do is totally legal by law, and significantly different in practice than taking data without informing anyone of your intent.

I guess the short answer to your question is that this is the United States. Everything is legal here, provided you do the paperwork first.

It was an internal database (from Capital One credit cards), they weren't allowed to use that data for analysis. This wasn't publicly accessible information.

See article: https://www.bloomberg.com/opinion/articles/2015-01-23/capita...

Because it was Capital One's internal data, which belongs to the shareholders. US insider trading laws are about theft, not about fairness (the markets require "unfairness" in this sense in order to perform price discovery).

The difference is public vs. non-public information. Doing something like counting cars in retailers parking lots is something any investor could do (or pay someone else to do). Trading using trends from non-public credit card transaction data isn't something that any "general public" investor could do on their own.

Also note this is about buying and selling securities, not selling consumer data for marketing purposes.

It's discussed in the link they added. The retailers shared the data with Capital One for specific business purposes, not for stock market analysis.