Lumia devices hold a “20% commercial market share in six countries” according to a Microsoft careers post (via Microsoft News). It specifically mentions the UK and Italy as two of those six countries. It later goes on to describe the job in more detail which gives a better idea of what “commercial market share” means in this case.
Their day to day description of the job includes trying to “reach business decision makers, IT pros and business-consumers.” Later in the post it lists primary responsibilities and many of those responsibilities include “Core Enterprise & SMB (small to medium business) Content.”
Based on the job description “commercial market share” is the most literal definition of the phrase, market share of commercial businesses. It doesn’t specify if this figure includes bring your own devices or if it only refers to devices purchased by enterprises and small to medium sized businesses.
These are very specific parameters to point out success. The post states their success in six countries but only names two of them, possibly meaning the other four are smaller markets though it could just be to save space in the post. It also is only referring to “commercial market share” which is a small subset of overall use. That being said, this is still a measure of success for Microsoft’s Lumia line of devices. Microsoft has a reputation of being well suited for business customers and that reputation carrying over to their mobile phone division would lead to a much larger user base.Further reading: Enterprise, Lumia, Market Share, SMB, Windows Phone