The Wall Street Journal warned on Tuesday that shares of Berkshire Hathaway Class A stock were approaching the $429,496.73 limit inherent to the Nasdaq digital format used to store stock prices. The stock passed that threshold Thursday, leading several popular stock ticker sites to show the price making wild oscillations of 99% magnitude. The Nasdaq site simply says there is no data currently available for the Class A shares of Berkshire Hathaway.
The root of the counting problem comes from the 32-bit architecture Nasdaq uses to store stock prices, per WSJ. Within that system, the largest number that can be stored is two to the power of 32 minus one, yielding the $429,496.7295 limit.
Most companies choose to split their stock into smaller portions as it grows in value. This doesn't affect the actual value of the underlying asset, but makes it more manageable for investors to trade. Berkshire Hathaway has a Class B stock that trades at a much lower price range, but its chairman and CEO Warren Buffet has insisted on maintaining the intact Class A price over the years.