We'll often hear about the "dash for trash" when a rally gets long in the tooth. Traders and investors start scooping up poorly performing names in hopes the rally will spread to underperformers. We need to keep an eye on strength, as well.

When weakness crops up in the best performing names, it becomes time to assess whether we are seeing some minor consolidation, which is healthy, or something more concerning.

The immediate answer is not often clear, so this isn't a process that is going to permit a trader to top tick the market. It's more of a symptom. The more symptoms a market possesses, the more we have to worry.

Biotech struggled again yesterday, but it has for the entire year, so I don't view that as a symptom. Gold and the miners also struggled, but these are often hedges, so again, not something weighing on the S&P 500 or the Nasdaq; however, when you look at a name like Broadcom (AVGO) , it does give you pause.

Broadcom has thrived in the red hot semiconductor space. The stock is up some 21.5% year to date and over 63% for the last 12 months. Those are impressive numbers for a $69 billion company. This isn't a small or even mid-cap stock. This is a name doing nearly $9 billion in sales.

Admittedly, the symptom, or concern, here is mild, but present. For two months, AVGO has marched steadily higher with an occasional pullback. Once it got above its 50-day simple moving average (SMA) in early July, it hasn't looked bad; however, the bullish channel tightened in August.

The lows became higher lows. The strength became stronger. The eight-day SMA was the only support needed and now we are threatening that. The issue isn't the stock needs to run on the eight-day SMA. The issue is initial support is still $3 lower, while the 50-day SMA is some $13 lower.

So, we're extended. It wasn't a problem in the past, but secondary indicators hint that it may be an issue now. The moving average convergence divergence (MACD), set as a longer-term view on this chart, looks ready to roll over should AVGO even continue to trade sideways, let alone lower.

The Full Stochastics and StochRSI have already rolled over. When trend and momentum both signal concern in front of price, it's worth a listen on an overextended chart. You'll often hear overbought can become more overbought. Well, we aren't overbought any longer.

If I had to choose a name to short, AVGO wouldn't be near the top of the list. Heck, it probably wouldn't be in the middle of the list. I still don't find shorting best of breed as the best of ideas, but AVGO is worth a watch as a hint of something more nefarious in the equity markets.