Original Equipment Manufacturer (OEM) versions of Microsoft software are licensed to PC manufacturers through two separate channels - large PC manufacturers and smaller System Builders. In the autumn of 2001, new program-specific COA labels were introduced with sophisticated security and tracking features, plus the How to Tell website address. A COA should always accompany the product that it is associated with. COAs cannot be purchased separately.

This COA has a holographic foil string on the right side.

This COA has an embedded thread woven through on the left side.

Versions of Office that are distributed with PCs built by a System Builder will have the wording "OEM Product" in big bold letters towards the upper left corner of the COA (as shown here in the COA label graphic image). Versions of Office that came from large PC manufacturers will have the name of the PC manufacturer on the COA label instead.

Note that prior versions of Microsoft application software will have a slightly different COA. Versions of Office that are distributed with PCs built by a System Builder will show the letter "D" in the middle left-hand section of the COA label, denoting it came through the distribution channel. Versions of Office that come from large PC manufacturers will not show the letter "D" on the COA label.