Certificates with extended validation are validated on company data, the company details are visible within the SSL certificate and the company name is being shown in a green address bar.
Extended validated certificate provides more trust to the visitors of a website since the visitors can see directly with which company is behind the website.
Next, to the domain validation where the website owner needs to verify that they are in control over the domain name where the certificate is requested for, the company data is also being verified.
Via a public register such as the Chamber of commerce the company data is being verified and the organization is also called to verify the company. There are also documents that needs be signed and sent to the CA.
The time of issuance for an extended validated certificate differs per supplier, due to a telephone verification and the validation of the company can take up between 2-5 working days.