"Most branded and white-box tablets, except Apple's iPad products, have adopted Android OS (Operating System). With Apple's market share declining constantly, Android OS has gained over 70% of the market," says Joen Yang, senior industry analyst with MIC. "Sales of tablets using Microsoft's OS have been low as these models are mainly for business purposes and have targeted niche markets."

To boost its market share, Microsoft stepped into hardware manufacturing and rolled out own-brand models named Surface in 2012. However, Surface received lukewarm market response and thus poor sales due to higher hardware requirements and prices.

Other vendors' tablets using Microsoft's OS also failed to boost Microsoft's market share as they were more expansive than rival counterparts and targeting business applications. As a result, Microsoft waived the license fee for 9-inch-and-below tablets in late 2012 to help vendors reduce overall costs.

Driven by this move, Taiwanese ODM (Own Design Manufacturing) companies increased the number of models based on Windows OS, pushing its market share from 1.5% to 4.6%.