The Nicholas II Fund primarily invests in the common shares of American companies with mid-range market values, particularly those believed to have strong prospects for expansion. The fund's management views a company's yearly sales figures and its market capitalization as the key metrics for determining its overall size. Specifically, they classify businesses with a market capitalization up to $3 billion as "small," those valued between $3 billion and $25 billion as "medium," and any company with a market capitalization greater than $25 billion as "large."