Despite what many apologists claim about front running being this very specific and formal type of activity that never happens because it's illegal and no one involved in finance ever commits crimes, the reality is that front running is not a technical term, neither in law nor in any academic or formal financial treatment.

Front running is an informal term that is used in many different domains to refer to when a principal acting on behalf of a client uses privately obtained information gained from that client to benefit at the client's expense. The term is used in finance, it's used in real estate dealings, heck there was even a scandal involving domain name registrars front running their clients:

http://www.circleid.com/posts/81082_network_solutions_front_...

The more formal and academic term is the principle agent problem:

https://en.wikipedia.org/wiki/Principal%E2%80%93agent_proble...

> the reality is that front running is not a technical term, neither in law nor in any academic or formal financial treatment.

There is literally a FINRA rule with with front running in the name (5270). It doesn't have to be a technical term for it to still have meaning (outside of Michael Lewis's intent to change its meaning). It specifically refers to a broker trading based on the knowledge of their client's intent to trade. The examples you give actually are instances of the true definition. It doesn't really happen in equities because of how automated and smooth that market is, but it certainly happens in other areas of finance.

The principal agent problem is much more general.