If you own the entire business (company) you own 100% - if you have equal partners, you each have 50%. If someone has 10% of the equity then they have ten percent of the shares (shareholder votes) in the business. Usually companies work on the basis of one class of shares and one vote per share.

A person with 51% of the equity (shares) cannot be defeated at a shareholder meeting so they control the business. (the remaining shareholders have 49%). If someone offers $200K for 20% then they value the business at $1 million (20% of 1,000,000 is $200K)

The price someone will pay for 51% is much greater because then they have control since control means deciding how much of the profits are distributed to shareholders and who is on the baord of Directors.

Percent of equity is the percent ownership of the business. Why is 51% important? Whoever owns 51% controls the company. They are the boss.

So I was watching some old episodes of "Shark Tank", and I realized that I never exactly got what "I want $220k for 20% equity in my company." I never got what that meant. Does it mean 20 percent of the business is investors? Do they both get profit still? And what does 51% equity mean since that's a common number.