What is the point of being able to exercise Dissenter or Appraisal Rights in a publicly traded company?

External question — Personal Finance Stack Exchange Author: Flux Original post: https://money.stackexchange.com/questions/152372 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. In the Interactive Brokers list of fees for Corporate Actions & Dividend Processing , there is a "$100 + external costs" fee for "requests to exercise Dissenter or Appraisal Rights". Under what conditions would I want to request to exercise Dissenter or Appraisal rights? If I disagreed with what a publicly traded corporation is planning to do, can't I simply sell my shares on the stock market, instead of paying $100+ to exercise my dissenter and appraisal rights?