Sector rotation is as old as the hills. Simply, the strong suffer, the weak recover.
Below we can see this distribution in the market leader IBB, and offset this with the accumulation in long forgotten GDX.
Richard Wyckoff logic allows the chartist to identify trend changing patterns. Both charts below require more time, but yes we have seen a very significant 'Change of Behavior' in each.
This simply means change is afoot, and pay attention!
"TIME is the most important factor in determining market movements and by studying the past records of the averages or individual stocks you will be able to prove for yourself that history does repeat and that by knowing the past you can tell the future. ... There is a definite relation between TIME and PRICE. ... Now, by a study of the TIME PERIODS and TIME CYCLES you will learn why tops and bottoms are found at certain times and why Resistance Levels are so strong at certain times and bottoms and tops hold around them. ... The most money is made when fast moves and extreme fluctuations occur at the end of major cycles." ~ William D Gann
"The first rule is not to lose. The second rule is not to forget the first rule." ~ Warren Buffett
"The main purpose of the stock market is to make fools of as many men as possible." ~ Bernard Baruch
"If past history was all there was to the game, the richest people would be librarians." ~ Warren Buffett
"If it's obvious, it's obviously wrong." ~ Joe Granville