Subject: Re: WEB Donations
Since then, he has given away about $50 billion in Berkshire stock and still owned 216,637 Class A shares based on the latest proxy in March. That interest is now worth $133 billion."

I believe the $50bn is the sum of the market values at the time each was given. The shares he has given away are now valued at a little under $160bn. Had he not donated them, his shareholding would be worth a little over $291 billion, which would leave him the richest person by quite a margin. Just the ~$80bn gap to #2 would be enough to get another person into the top 20.

Jim