Assuming a holo makes $30,000 a month, that would be $360,000 a year. Let's pretend that SCs, memberships, merch sales, promotional opportunities, etc don't exist. Now, let's say Cover takes 30% of that. Down to 252k. YouTube takes another 30% of that. $176,400.
Now we have to factor in taxes. Assuming the holo lives in the US, $75,874 of that income is taxed at 24%. $53,374 is taxed at a 22% rate. $35,549 is taxed at 12%. And the remaining $11,600 is taxed at 10%. That lowers their income to $147,019.08 annually.
Now, we have to consider that because these girls are living in the US, they probably have to pay for health insurance. That will vary depending on who their provider is, what their plan is, and even what state they live in.The US average monthly cost for health insurance for 2024 is $477, so $5,724 a year. We are now down to $141,295.08. Thankfully, that's barely a dent!
But what about housing? I think we can assume that they have to live in a house of sorts. I doubt many holos stream from public libraries. So let's pretend that this imaginary holo lives in SoCal. Los Angeles, to really try and paint a grim picture of the cost of living. Average rent in for a 2 bedroom apartment in LA this year was $2,953 a month, or $35,436 a year. We are down to $105,859.08.
So it's possible that the ENs are millionaires, if we assume the EN has been in hololive for 4 years and has a very dedicated (and rich) fanbase, multiple promotional opportunities, and has a constant stream of endeavors that result in a substantial increase in net income. That is to say, the only EN that could realistically be a millionaire would be the one and only Calliope "Your Boy" "Money Mori" Mori.
