Can you tell me what percent of your company needs to be recognized as certified Level 2 in order to state that your entire company is Level 2?
Contrary to popular belief, an entire company rarely achieves CMMI ML2 (or any other level for that matter). There is a concept in the SCAMPI Appraisal Method called an "organizational unit" that defines the target organization within a company that is to be appraised. When the appraisal is complete, you may say that your company has reached ML2, but in reality perhaps only a single organization in your company has reached that goal. That information is displayed on the SEI's appraisal results page, although I would argue that most people aren't aware of the concept when they look at.
The definition of the Organization Unit, or OU in Lead Appraiser speak, is something you discuss, and agree upon, with your Lead Appraiser. It needs to be credible (such as an entire location (Dayton, OH), a product line (mainframe payroll systems), a type of technology (all web development), or a management tree (everyone reporting to the Director of Engineering. . .). Inside of your OU, you and the Lead Appraiser will select a group of projects (3 or more) that is a representative sampling of the OU. Again, this is something you and LA agree on in advance.
A poor example is one where the OU is "all projects with the charge code 145387.
When it's all over (and if you're successful) if you're like most companies you will say [company name] is CMMI ML2. Some are more specific, and name the OU, but it my experience, most do not (right or wrong).
When you enter Baltimore-Washington airport there is a huge banner across the road that says "Lockheed-Martin - CMMI Level Five." I can assure you that, while they have achieved ML5 within some organizations, the "entire company" has not.
One exception I can think of is a company whose sole business is writing software in a single location. Perhaps then the company is ML5.
So, there are two ways to slice it. First, the organizational unit is agreed upon, and then a set of representative projects is selected. Make sense?