What is this altcoin and why is it rising so rapidly? A market cap of 25 billion dollars is really hard to get into; if you buy in, it might actually become 250.
The valuation of Circle at 20% to 30% of Coinbase is quite reasonable, and earning 500 million dollars a year is not a problem. Based on a price-to-earnings ratio of 30, that puts it at 15 billion dollars, so it's better to wait until it's below 15 billion dollars to buy.
Most investments were made at a valuation of 4.5 billion dollars or higher, so at least the book return is already 5 times.