Pre-emptive rights give investors the right to maintain their percentage ownership of a company by purchasing additional shares when new shares are issued. This protects investors from dilution of their stake if new shares are issued at a lower price than what the investors originally paid. Pre-emptive rights also incentivize companies to issue stock at higher valuations. However, some companies choose not to offer these rights because it can make raising equity capital through new share issuances more inconvenient.