Stock in very small companies whose market capitalization, reflecting the total value of the company's stock, is low or "micro." Microcap stocks tend to be low priced and trade in low volumes.
Microcap Stock: A Guide for Investors
Microcap Fraud spotlight
Investor Alert—Don’t Trade on Pump-And-Dump Stock Emails
Investor Alert: Social Media and Investing – Avoiding Fraud
Pump and Dump Schemes