Small and medium-sized enterprises (SMEs, also small and medium enterprises) or small and medium-sized businesses (SMBs) are businesses whose personnel numbers fall below certain limits.
Small enterprises outnumber large companies by a wide margin and also employ many more people. SMEs are also said to be responsible for driving innovation and competition in many economic sectors.
Petrakis and Kostis (2012) explore the role of interpersonal trust and knowledge in the number of small and medium enterprises. They conclude that knowledge positively affects the number of SMEs, which in turn, positively affects interpersonal trust. Note that the empirical results indicate that interpersonal trust does not affect the number of SMEs. Therefore, although knowledge development can reinforce SMEs, trust becomes widespread in a society when the number of SMEs is greater.
Most of Egypt's businesses are small-sized, with 97 percent employing fewer than 10 workers, according to census data released by state-run statistics body CAPMAS.
Medium-sized enterprises with 10 to 50 employees account for around 2.7 percent of total businesses. However, big businesses with over 50 employees account for 0.4 percent of all enterprises nationwide.
The data is part of Egypt's 2012/13 economic census on establishments ranging from small stalls to big enterprises. Economic activity outside the establishments – like street vendors and farmers, for example – were excluded from the census.
The results show that Egypt is greatly lacking in medium-sized businesses.
Seventy percent of the country's 2.4 million businesses have only one or two employees. But less than 0.1 percent – only 784 businesses – employ between 45 and 49 people.
In Ethiopia, there are SME enterprises funded by the government that are becoming sources of work.
In Kenya, the term changed to MSME, which stands for "micro, small, and medium-sized enterprises".
For micro enterprises, the maximum number of employees is up to 10 employees. For small enterprises, it is from 10 to 50. For medium enterprises, it is from 50 to 100.
The Central Bank of Nigeria defines small and medium enterprises in Nigeria according to asset base and number of staff employed. The criteria are an asset base that is between N5 million to N500 million, and a staff strength that is between 11 and 100 employees.
In Somalia, the term is SME (for "small, medium, and micro enterprises"); elsewhere in Africa, MSME stands for "micro, small, and medium enterprises". An SME is defined as a small business that has more than 30 employees but less than 500 employees.
In the National Small Business Amendment Act 26 0f 2003, micro-businesses in the different sectors, varying from the manufacturing to the retail sectors, are defined as businesses with five or fewer employees and a turnover of up to R100,000 ZAR. Very small businesses employ between 6 and 20 employees, small businesses employ between 21 and 50 employees. The upper limit for turnover in a small business varies from R1 million in the Agricultural sector to R13 million in the Catering, Accommodations and other Trade sector as well as in the Manufacturing sector, with a maximum of R32 million in the Wholesale Trade sector.
Medium-sized businesses usually employ up to 200 people (100 in the Agricultural sector), and the maximum turnover varies from R5 million in the Agricultural sector to R51 million in the Manufacturing sector and R64 million in the Wholesale Trade, Commercial Agents and Allied Services sector.
A comprehensive definition of an SME in South Africa is therefore any enterprise with one or more of the following characteristics:
Under section 7 of the Micro, Small and Medium Enterprises Development (MSMED) Act, 2006, the Indian government defined the size of micro, small, and medium enterprises as:
(i) a micro enterprise, where the investment in plant and machinery does not exceed twenty-five lakh rupees
(ii) a small enterprise, where the investment in plant and machinery is more than twenty-five lakh rupees but does not exceed five crore rupees; or
(iii) a medium enterprise, where the investment in plant and machinery is more than five crore rupees but does not exceed ten crore rupees;
(b) in the case of the enterprises engaged in providing or rendering of services, as—
(i) a micro enterprise, where the investment in equipment does not exceed ten lakh rupees;
(ii) a small enterprise, where the investment in equipment is more than ten lakh rupees but does not exceed two crore rupees; or(iii) a medium enterprise, where the investment in equipment is more than two crore rupees but does not exceed five crore rupees.
Businesses that are declared as MSMEs and within specific sectors and criteria can then apply for "priority sector" lending to help with business expenses; banks have annual targets set by the Prime Minister’s Task Force on MSMEs for year-on-year increases of lending to various categories of MSMEs.
|Type||Maximum assets, Rp||Maximum revenue, Rp|
An annual revenue of Rp 50 billion is approximately equal to USD 3.7 million as of November 2017.
In Bangladesh, Bangladesh Bank defines Small and medium enterprises based on Fixed Asset and Employed Manpower and they are definitely not Public Limited Co. and requires these characteristics -
|Serial No||Sector||Fixed Asset other than Land and Building (Tk)
SE (Small Enterprises) & ME (Medium Enterprises)
|01||Services||For SE 50,000 - 5000,000 &
For ME 50,00,000 - 10,00,00,000
|SE - 25 & ME - 50|
|02||Business||For SE 50,000 - 50,00,000 &
For ME 50,00,000 - 10,00,00,000
|SE - 25 & ME - 50|
|03||Industrial||For SE 50,000 - 1,50,00,000
For Me 1,50,00,000 - 2,00,00,000
|SE - 50 & ME - 150|
With effect from 1 April 2011, the definition of SMEs is businesses with annual sales turnover of not more than $100 million or employing no more than 200 staff. 
The criteria for defining the size of a business differ from country to country, with many countries having programs of business rate reduction and financial subsidy for SMEs. According to the European Commission, the SME are the enterprises that meet the following definition of staff headcount and either the turnover or balance sheet total definitions:
|Company category||Staff headcount||Turnover||Balance sheet total|
|Medium-sized||< 250||≤ €50 million||≤ €43 million|
|Small||< 50||≤ €10 million||≤ €10 million|
|Micro||< 10||≤ €2 million||≤ €2 million|
In July 2011, the European Commission said it would open a consultation on the definition of SMEs in 2012. In Europe, there are three broad parameters which define SMEs:
The European definition of SME follows: "The category of micro, small and medium-sized enterprises (SMEs) is made up of enterprises which employ fewer than 250 persons and which have an annual turnover not exceeding 50 million euro, and/or an annual balance sheet total not exceeding 43 million euro." In order to prepare for an evaluation and revision of some features of the small and medium-sized enterprises definition European Union established public consultation period from 6 February 2018 to 6 May 2018. Public consultation is available for all EU member country citizens and organizations. Especially, national and regional authorities, enterprises, business associations or organizations, venture capital providers, research and academic institutions, and individual citizens are expected as the main contributors. 
EU member states have had individual definitions of what constitutes an SME. For example, the definition in Germany had a limit of 255 employees, while in Belgium it could have been 100. The result is that while a Belgian business of 249 employees would be taxed at full rate in Belgium, it would nevertheless be eligible for SME subsidy under a European-labelled programme.
SMEs are a crucial element in the supplier network of large enterprises which are already on their way towards Industry 4.0. According to German economist Hans-Heinrich Bass, "empirical research on SME as well as policies to promote SME have a long tradition in [West] Germany, dating back into the 19th century. Until the mid-20th century most researchers considered SME as an impediment to further economic development and SME policies were thus designed in the framework of social policies. Only the Ordoliberalism school, the founding fathers of Germany's social market economy, discovered their strengths, considered SME as a solution to mid-20th century economic problems (mass unemployment, abuse of economic power), and laid the foundations for non-selective (functional) industrial policies to promote SMEs."
The SME sector in Poland generates almost 50% of the GDP, and out of that, for instance, in 2011, micro companies generated 29.6%, small companies 7.7%, and medium companies 10.4% (big companies 24.0%; other entities 16.5%, and revenues from customs duties and taxes generated 11.9%). In 2011, out of the total of 1,784,603 entities operating in Poland, merely 3,189 were classified as "large", so 1,781,414 were micro, small, or medium. Companies of the SMEs sector employed 6.3 million people out of the total of 9.0 million of labour employed in the private sector. In Poland in 2011 was 36.2 SMEs per 1,000 of inhabitants.
In the UK a company is defined as being an SME if it meets two out of three criteria: it has a turnover of less than £25m, it has fewer than 250 employees, it has gross assets of less than £12.5m. Many small and medium-sized businesses form part of the UK's currently growing Mittelstand, or Brittelstand as it is also often named. These are businesses in Britain that are not only small or medium but also have a much broader set of values and more elastic definition.
The Department for Business Innovation and Skills estimated that at the start of 2014, 99.3% of UK private sector businesses were SMEs, with their £1.6 trillion annual turnover accounting for 47% of private sector turnover.
In order to support SMEs, the UK government set a target in 2010 "that 25% of government’s spend, either directly or in supply chains, goes to SMEs by 2015"; it achieved this by 2013.
Industry Canada defines a small business as one with fewer than 100 paid employees and a medium-sized business as one with at least 100 and fewer than 500 employees. As of December 2012, there were 1,107,540 employer businesses in Canada, of which 1,087,803 were small. Small businesses make up 98.2 percent of employer businesses, medium-sized businesses make up 1.6 percent of employer businesses and large businesses make up 0.1 percent of employer businesses. In 2012, over 7.7 million employees, or 69.7 percent of the total private labour force, worked for small businesses and 2.2 million employees, or 20.2 percent of the labour force, worked for medium-sized businesses. In total, SMEs employed about 10 million individuals, or 89.9 percent of employees. Canadian high-growth firms are present in every economic sector and are not just concentrated in knowledge-based industries. In terms of employment, the highest concentrations of high-growth firms in Canada during the 2006–2009 period were in construction (4.9 percent of all firms); business, building and other support services (4.6 percent); and professional, scientific and technical services (4.5 percent). In 2011, only 10.4 percent of SMEs exported. Nonetheless, they were responsible for $150 billion, or about 41.0 percent, of Canada's total value of exports.
Corporations in Canada are generally taxed at 29% federally. Canadian Controlled private corporations receive a 17% reduction in the tax rate on taxable income from active businesses up to $500,000. This small business deduction is reduced for corporations whose taxable capital exceeding $10M, and is completely eliminated for corporations whose taxable capital exceeds $15M. It has been estimated that almost $2 trillion of Canadian SMEs will be coming up for sale over the next decade which is twice as large as the assets of the top 1,000 Canadian pension plans and approximately the same size as Canadian annual GDP.
The small and medium sized companies in Mexico are called PyMEs, which is a direct translation of SMEs. But there's another categorization in the country calledl MiPyMEs. The MiPyMEs are micro, small and medium sized businesses, with an emphasis on micro which are one man companies or a type of freelance.
In the United States, the Small Business Administration sets small business criteria based on industry, ownership structure, revenue and number of employees (which in some circumstances may be as high as 1500, although the cap is typically 500). Both the US and the EU generally use the same threshold of fewer than 10 employees for small offices (SOHO).
Also in the United States small and medium-sized manufacturers are referred to as SMM's  which the U.S. Department of Energy classifies as having gross annual sales below $100 million, Fewer than 500 employees at the plant site, and annual energy bills more than $100,000 but less than $2.5 million.
In Australia, a SME has 200 or fewer employees. Microbusinesses have 1–4 employees, small businesses 5–19, medium businesses 20–199, and large businesses 200+. Australian SMEs make up 97% of all Australian businesses, produced one third of total GDP, and employ 4.7 million people. SMEs represent 90 per cent of all goods exporters and over 60% of services exporters.