You can check out above graph to see how the market cap of IOS token has changed over time. The market cap value depends on the value of IOS token on that particular day and number of IOS token in supply at that day.

How is IOS token Market Cap calculated?

The IOS token Market cap is calculated using a simple formula. You can find it below:

IOS token Market Capitalization in USD = Number of IOST in supply X Price of one IOS token in USD

Since the price of IOS token is highly volatile you can see the market cap going up and down a lot. Sometimes price and market cap are not linear to each other due to increase in the supply of coins in the market and stable or decrease in the price of the coin. So you can say that it's not simple to predict the market cap of IOS token or predict the price of IOS token.