Small and medium sized enterprises (SMEs) are often grouped together in analyses. It's actually not a perfect way of grouping companies. A small company may consist of a few people or a family acting together to earn subsistence incomes while there is no other employment available. The company may not do much in the way of good company practice. A medium sized company has done something well at some point in the past, otherwise it wouldn't have reached medium size. It has been at least quite good at being a company.
SMEs don't form a flawless group for contrast with large companies, either. A medium sized company may have some characteristics in common with small companies, but also some in common with large companies. For example, the investment rates of medium sized companies may lie between the rates of small and large companies. Here are some corporate statistics from the Great Lakes region, averaged over all companies split by company size:
The table shows that medium sized companies often have characteristics that lie between small and large companies. The percentage of the companies owned by private domestic owners is close for small and medium companies. On the other hand, the percentage of the companies owned by the largest owner is close for medium and large companies. So while talking about SMEs can sometimes be sensible, at other times it may be better to talk about Medium and Large Enterprises, and at other times to talk about just medium sized companies.