"He did the bookkeeping himself and prepared his own tax returns. With its numbers, accuracy, and the measuring of results, the recordkeeping aspect of the job pleased him."
[...]
"Warren was still handling all the money and doing all the clerical work himself: filing the tax returns,..."
[...]
"'Bill started trying to convince me to get a computer. I said, I don’t know what it’s going to do for me. I don’t care how my stock portfolio is doing every five minutes. And I can do my income taxes in my head.'"
Seems like indeed he is doing them himself (his personal tax bill; to do it for Berkshire, they surely have hired help)
"He did the bookkeeping himself and prepared his own tax returns. With its numbers, accuracy, and the measuring of results, the recordkeeping aspect of the job pleased him."
[...]
"Warren was still handling all the money and doing all the clerical work himself: filing the tax returns,..."
[...]
"'Bill started trying to convince me to get a computer. I said, I don’t know what it’s going to do for me. I don’t care how my stock portfolio is doing every five minutes. And I can do my income taxes in my head.'"
Seems like indeed he is doing them himself (his personal tax bill; to do it for Berkshire, they surely have hired help)