many ways to explain why AAPL is weak.

1. The market is driven by the short covering before year end. Because AAPL is such a good company with reasonable valuation, it is not a target of short seller.

2. ETF pegged to big caps are not getting inflow as much as ETF pegged to small and mid caps.

3. big fund managers are off the desk and heading for vacations while smaller managers are still on the desk to window dress the year end.

and so on so on.