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

How is IOTA Market Cap calculated?

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

IOTA Market Capitalization in USD = Number of IOT in supply X Price of one IOTA in USD

Since the price of IOTA 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 IOTA or predict the price of IOTA.