Stocks held for more than one year are given long-term capital gain treatment.
Less than one year is short-term gain.
There is a rule on Small Business Stock held longer than 5 years. You would know if you had this stock.
Here is a link to an article on this.
https://thismatter.com/money/tax/small-business-stock-sales.htm
A C-corporate can issue a certain type of stock, called §1244 stock, which receives preferential tax treatment if the shareholder suffers losses on the stock.