You are right that the market breadth is still narrow and that is a risk for the market uptrend. But clearly there are two trends visible and let us focus on both these trends that are driving indices higher.

As you rightly said, there is surely a market leader effect that is visible. The market leadership has been limited to a handful of stocks like RIL, TCS, HDFC, HDFC Bank, Infosys, ICICI Bank, Kotak Bank etc. The combination of size and quality continues to attract funds to these stocks even at rich valuations. This has kept the stock markets buoyant even as the economy has lagged.

But more importantly, there is a very subtle sectoral revival that is also seen in the markets today. Something has changed in the last few weeks and sectors that were long ignored have suddenly taken centre stage. For example, telecom stocks are back in action with the AGR issue sorted out. Secondly, metals have seen a lot of buying interest due to the trade deal and the expected stimulus by China. Lastly, buoyant oil prices have led to revival of interest in stocks in the oil upstream and refining sectors.