Medium and small size private enterprise

Privately operated mid- and small-scale enterprise

Privately operated mid- and small-scale enterprise

Private SMEs

medium and small scaled private-run enterprises

small private firm,
small private company.

除了大的都是小的。没有必要讲中小型，也不说 enterprise 。-run 是画蛇添足。

small business,其实没有所谓“中型企业”一说。

medium- and small-sized private enterprises