While quad-witching on index-rebal day usually leads to odd sights in the market, there was little confusion about what happened at the open, when as Bloomberg first noted, Apple shares dipped 0.1% lower after a size seller dumped 9.24 million AAPL shares in a single block trade at the Nasdaq open, at a price of $141.00, amounting to just over $1.3 billion worth of AAPL stock.
It is unclear as of this moment whether Warren Buffett was the buyer.