As AAPL goes...

A good quality leadership stock in a bear market is like a camp counselor in a horror flick; generally the counselor survives in order to tell the tale and pass on the mythos of horror only to find themselves the first victim of the sequel. Looking over the landscape of leaders, many managed to escape the first down leg from late July into early August unscathed, but as the market appears to be deteriorating further, it is worth keeping an eye on these.

Stan Weinstein shares a method in Secrets or Profiting in Bull and Bear Markets entitled "As GM goes"

1. Four Month Rule: If GM doesn't make a new high (or low) within four months it is a signal that GMs prevailing trend is reversing.
2. When it completes a Stage 3 top and breaks down into Stage 4, it's time to worry even if a new GM high was hit last month.
3. When GM refuses to make a new high (or low) in tandem with the DJI and the other leading averages, it's an early warning that you'd better be alert.

His logic behind this is:

The market is not a democracy.  The bullish and bearish votes that each stock casts toward the major trend most definitely do not count equally.  The most heavily traded and institutional favorites matter far more... Of all these shakers and movers, there is one that you must always keep your eyes glued to --General Motors.  Never listen to the message of this key stock in a vacuum, but when it flashes a major signal that is in sync with the majority of the gauges in this chapter, do not ignore it! pg 297-297

 It's safe to say that General Motors does not wield the significance and sway it once had.  There are new leaders that have emerged and clearly the most watched and mentioned is Apple.  Not only is it discussed and defended with zealotry on message boards, chat rooms and social media outlets, but people are also willing to make pilgrimages cross country to where it all began or will wait in line for hours if not days to be the first to get a new product.  In fact, recent studies involving fMRI scans have indicated that Apple has the same effect upon its followers as religions do among theirs.

So, while it is simple enough to replace GM with APPL, there are a number of other institutional darlings that should also grab one's attention.  Stocks such as AMZN, BIDU, CMG and PCLN are note worthy in their own right.  Given that many of these stocks managed to act well and stave off the first wave of clawing, how these stocks behave given the current market action will be telling.  If there is another round of clawing, will these stocks survive the opening scene of the sequel?

AAPL

AMZN

BIDU

CMG

PCLN