Optionality basically just means that there isn't a straightforward linear relationship between the price of something and how much you earn out of it. It's a v

Optionality basically just means that there isn't a straightforward linear relationship between the price of something and how much you earn out of it. It's a very general term. With preferred shares, investors have the option of taking either some percent of the company, or of instead taking a flat payment equal to their original investment (or more). For example, if a venture investor invested $100 into your lemonade stand, they could choose either to get the first $100 when you sold the stand, or to get 20% of the sale price. As long as you sold it under $500, they would take their $100 back, but if you sold it over $500 they would take 20%. If you sold it under $100, they would get all of it. That's the downside protection, since you'd be left with less than 80% of the proceeds even though nominally you own 80% of the business.