BRK total return from inception to 2025: about 5,502,284% (55,000x gain)

S&P500 total return over the same period: about 39,054% (390x gain)

$1 in BRK would be $55k today. $1 in S&P500 would be $390 today. Therefore, following the hypothetical 99% drop, 1% of Berkshire return would be $550, still well above the S&P500's $390.