Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Robert Kelly is managing director of XTS ...

The law of marginal utility states that customer satisfaction decreases with each unit purchased. So, the more your customers purchase, the less satisfaction they get from each additional purchase. If ...

Andriy Blokhin has 5+ years of professional experience in public accounting, personal investing, and as a senior auditor with Ernst & Young. Erika Rasure is globally-recognized as a leading consumer ...