Subject: Re: Back of the envelope
For "P/B" in March 2024 and September 2004 I'm using the ending BV for the quarter For completeness we can also calculate the P/BV using the starting BV for the quarter.

March stock repurchases:
Repurchase price = $623,206/A-share equivalent
Starting BV for quarter = $389,372, P/starting BV = 1.601
Ending BV for quarter = $397,627, P/ending BV = 1.567

September stock issuances:
Issue price = $456.70/B-share = $685,052/A-share
Starting BV for quarter = $418,806, P/starting BV = 1.636
Ending BV for quarter = $437,589, P/ending BV = 1.566

Since March and September are close to the end of Q1 and Q3 respectively, I used the P/ending BV (1.567 for both) as the estimate of IV.