>>38370450So as a private company, the stock of the company is owned by private investors. In the case of Anycolor it was owned 51% by Riku and 49% by a bunch of VC companies.
Now Anycolor decides to IPO. That means they issue more stock and sell it on the open market. There's an initial auction to set the price. In the case of Anycolor the new stock was about 10% additional stock. So Riku still owns 46%, other investors own 44%, and 10% is sold to the public. The 10% stock was sold on the market and the final auction price was somewhere above 5000 yen a share. I don't want to bother digging it up but it ends up being about 2.7 million shares at more than 5000 yen each, so more than 13.5 billion yen, or more than 100 million usd. That money goes to the company.
So Anycolor kept just over 100 million usd out of going public, the rest of the money exchanged for their stock since isn't in company hands. When someone sells their stock, the person at the other end of the transaction paying them money is another private individual (or more likely, another company).