Eoin Treacy's view Although the Index officially has a modified cap weighting which limits the influence of any one company to 24%, a look at the market cap of its constituents as they currently stand suggests none are close to that ceiling. Apple, for example, currently represents approximately 11.9% of the Index's market cap. With the Nasdaq posting new 12-year highs I thought it might be instructive to examine which sectors are contributing most to the recent strength.

I compiled this table of the Nasdaq-100's subsectors by market cap. Computers (12.55%) Web Portals/ISP (9.68%), Medical-Biomedical, Genetics (9.44%) Applications Software (8.14%), Electronic Components-Semiconductors (6.44%) and E-Commerce/Products (5.32%) account for 51.5% of the Index's market cap. Another way of looking at it is that its top-10 companies; Apple, Google, Microsoft, Vodafone, Amazon, Cisco Systems, Qualcomm, Intel, Comcast and Facebook account for nearly half its market cap (49.5%).

What jumps out to me from the above statistics is that while biotech is the third largest subsector, none of its companies make the top-10 in terms of their market cap. Biotech represents an area of research which not only holds great promise but where therapies are increasingly reaching commercial utility. The survivors of the bust that enveloped the sector nearly 13 years ago have become some of the titans of this industry. It seems reasonable to expect some will eventually be among the largest companies on the Index. (Also see Comment of the Day on October 28th 2011 and on a number of subsequent occasions for reviews of biotech shares).

At present Gilead Sciences is the 11th largest company on the Nasdaq. The share broke out of a five-year range a year ago and has since doubled. The largest reaction to date found support in the region of the 200-day MA from late June and the most recent reaction found support in the region of the previous peak. A sustained move below $55 would be required to question medium-term upside potential. Celgene has a similar pattern.

Biogen experienced a powerful breakout in 2011 and accelerated to its May peak below $250. It has been consolidating with an upward bias since and a sustained move below the 200-day MA, currently near $200, would be required to question medium-term scope for additional upside.

Amgen experienced a similar base formation completion in 2011 and has been consolidating in the region of the May peak for the last few weeks. A sustained move below $100 would be required to begin to question the consistency of the overall advance. Regeneron has formed an orderly consolidation since the May peak and is now retesting its highs.

Alexion Pharmaceuticals hit a medium-term peak near $120 a year ago and a sustained move above that level would reaffirm medium-term demand dominance.

In the medical information technology sector Cerner found support last week in the region of the 200-day MA and a sustained move below $45 would be required to question medium-term uptrend consistency.

In addition to biotech, the entertainment sector is particularly noteworthy. A great deal of speculation has been taking place about the future of the television, mobile consumption of media and enhanced wrist watches. However, regardless of which technology eventually prevails the providers of programming are likely to benefit from increased demand for their services. The same logic is evident in the wireless internet market where the providers of internet connectivity are prospering from increased demand for content.

Comcast found support in the region of the 200-day MA from late last month and the benefit of the doubt can continue to be given to the upside provided it continues to hold above $38. Liberty Global has a broadly similar pattern.

Viacom broke out of an almost two-year range in January and has become somewhat overextended as it tests the $80 area. However, a break in the progression of higher reaction lows, currently near $77 would be required to check momentum.

Twenty First Century Fox has held a progression of higher major reaction lows since early 2009 and while somewhat overextended at present, a sustained move below $30 would be required to begin to question the consistency of the advance.

Following the announcement that it was buying out Vivendi's holding, Activision Blizzard surged out of a yearlong first step above its lengthy base. The share found support last week in the region of $16 and while there is room for some additional consolidation, a sustained move below the 200-day MA would be required to question recovery potential.

Broadly speaking the Index is susceptible to a pause considering the speed with which it has rallied of late. However, the strong chart patterns exhibited by so many of its constituents and the fact that it plays host to some of the world's most exciting companies suggests any pullback will be limited to a reversion towards the mean.