Answer:
In business, SME stands for Small to Mid-sized Enterprise.
In order to conduct their operation, Large Enterprises tend to invest heavily on assets that they use to produce a certain product. (such as expensive machinery, long-term Advertising deal, etc)
This investments will cut their cost of production in the long run. BUT, they have to stick to one single type of product. Otherwise, their investment will go to waste.
SME rarely made that type of investment. Typically, their cost of production tend to be higher compared to Large Enterprises. But they can quickly changes and adjust their product following consumer's demand without having to lose a lot of initial investment.