When combining the data for those countries for which reasonably good data are available, SMEs account for 52% of private sector value added, which provides a reasonable estimate for the sector’s global economic contribution (ACCA 2010).
The contribution of SMEs to economic fundamentals nonetheless varies substantially across countries: from 16% of GDP in low-income countries (where the sector is typically large but informal) to 51% of GDP in high-income countries. Figure 1.1 on page 8 illustrates the contribution of the SME sector to GDP, including both the formal sector and estimates of the informal sector, which is disproportionately large in low-income countries. History and legal tradition can also play a very important role. For instance, former Soviet countries tend to have disproportionately small SME sectors, even when controlling for per capita income (Ayyagari et al. 2003).
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