Bellwether company

A Bellwether company is any entity in a given arena that can influence trends for  future happenings.

In the Stock Market , a bellwether UK is the stock of a company that is regarded as a leader in its given industry. For example  JP Mrogan Chase is a bellwether stock. As one of the major banks in the US, it sets the tone for the rest of the industry. JPMorgan Chase also has contracts with companies in other industries so its performance is reflected in other sectors of the market.

In Sociology the term is applied in the active sense to a person or group of people who tend to create, influence, or set  trends.