> Is there a limit to how many shares a company can issue? No, a board can technically issue shares unto infinity. There is no guarantee of scarcity, no guarantee they will not raise more money.
The scarce asset is the company, not the shares. Yes, they can issue more shares, but those shares still represent the same company plus the new investment money raised by raising the shares. They're not creating more company out of thin air when they issue more shares.
EDIT: To clarify some misconceptions in the comments below: When a company sells more shares into the market they are not simply diluting away existing shareholders. The keyword is that they are selling shares, meaning they take money in exchange for shares. The company's value increases by the amount of money they take in exchange for the sale.
Example: If a company is worth $1,000,000 and has 1,000,000 shares outstanding, each share is worth $1. If the company decides to sell another 100,000 shares and the market buys them at $1/each, there are now 1,100,000 shares outstanding and the company is now worth $1,100,000 because they took in $100,000 of cash via share sales. Existing shareholders have not lost any money or value.