Apple Inc AAPL investors are bracing for a significant shake-up as the quarterly rebalancing of market index funds coincides with a rare triple witching event, a financial phenomenon that only intensifies market volatility.Busiest Rebalancing In Four Years To Boost Apple With $250 billion in stock adjustments underway, the iPhone manufacturer could emerge as one of the biggest beneficiaries. A notable shift comes from Berkshire Hathaway BRK BRK trimming its stake, increasing the share count used by index pr ...