Subject: Re: How high will this thing go?
About a year ago Berkshire traded at $420.56

I'm pretty sure that throughout 2023, it didn't trade above 400. I would remember because I was selling puts almost monthly (in hopes of snagging some shares at good prices. They all expired worthless except for the March 305s that were exercised and assigned to me near their expiration. Later in the year (2023), I gave up on my attempts at acquiring shares via put sales and instead just bought outright in the 340s and 350s in November and December.