Christina Majaski writes and edits finance, credit cards, and travel content. She has 14+ years of experience with print and digital publications. Robert Kelly is managing director of XTS Energy LLC, ...

Indicator species are living organisms that tell us that something has changed or is going to change in their environment. They can be easily observed, and studying them is considered a cost-effective ...

Elvis Picardo is a regular contributor to Investopedia and has 25+ years of experience as a portfolio manager with diverse capital markets experience. Robert Kelly is managing director of XTS Energy ...