With the major indices again at new highs, how to describe the market's relentless advance? I've been using the phrase "The Great Sector Rotation" to describe this, the idea that in 2013, no sectors have lagged for very long.
Art Cashin has suggested calling it "The Great Relay" because all year the sectors have taken turns passing the leadership baton back and forth.
So at one point, for example, technology may outperform, but never for very long. It quickly falls back, and something else--Industrials, Materials, Healthcare, whatever--takes its place.
That's what's remarkable: the whatever part. Usually there is a wider distribution of winners and losers, even when you are talking about ten sectors in the S&P 500.
But this year, every single sector in the S&P 500 is up at least 10 percent, and five are up 20 percent or more. There are no losers--just relative laggards. Nothing falls apart.
And even the laggards are doing well.
Look at the biggest sectors, and what they are doing this month alone:
The three biggest sectors by market cap are Tech, Financials, and Healthcare. All three are up roughly five percent this month.
Those three sectors alone are nearly 50 percent of the market cap of the entire S&P 500.
See what I mean? It has indeed become a relay.
—By CNBC's Bob Pisani