Wiktionary
round lot
n. a block of shares of stock that is a multiple of some number, usually 100
Wikipedia
Round lot
A round lot is a normal unit of trading of a security, which is usually 100 shares of stock. Each stock exchange has its own regulations regarding round lot sizes: they can range anywhere from 1-100 shares, depending on the exchange. Any quantity less than this normal unit is referred to as an odd lot.
Usage examples of "round lot".
I wasn't about to admit that was my view, not publicly anyway, but I was already convinced that the present course of the Guard would pull down a round lot of cultures, whether or not that destruction was really necessary.