You can check out above graph to see how the market cap of 0x has changed over time. The market cap value depends on the value of 0x on that particular day and number of 0x in supply at that day.

How is 0x Market Cap calculated?

The 0x Market cap is calculated using a simple formula. You can find it below:

0x Market Capitalization in USD = Number of ZRX in supply X Price of one 0x in USD

Since the price of 0x 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 0x or predict the price of 0x.