As I discuss EV SSL with a variety of online businesses, one question I get a lot is about the name that appears adjacent to the address bar in compatible browsers. The question goes something like this, "We do business under the well-known brand of HipCoolStuff, but our company is actually called Old Stodgy Holding Corporation. We don't want the Old Stodgy name on our Web site. Nobody knows us by that name, and it's not the brand identity we choose to present to the public. What can we do about that?"
The answer is that you're allowed to use any legal trade name that you possess in that address bar. A business may obtain EV certificates under an organization name that is a legally registered trade name of the organization in question (referred to in the EV guidelines as "Assumed Name"). VeriSign or the other CA must authenticate the legal status of that trade name as a valid name registered to the Organization before we are allowed to issue the certificate. Then when the certificate appears on the site, you will see the trade name first and then a parenthetical note with the legal name of the organization. For example, HSBC also owns the first direct Internet bank. On the first direct site<, the organization name is not "HSBC Holdings." Rather it is "first direct Bank (HSBC Holdings plc)."
In my experience organizations are pretty buttoned up on trade names. The risks involved with building a brand on what is not a legal trade name are pretty unacceptable, and I don't recall ever having bumped into a company that got that one wrong. So if there's a name that you're trading under as your main brand, I expect you'll be allowed to put it in your EV SSL Certificates. If your company has several or many of these trade names, you can hold active certificates under more than one trade name concurrently (although each certificate will be limited to a single trade name for its duration, of course).