One important note - when HSI touches the pink line, that almost perfectly timed the market tops in 2000, in 2007, and also timed the 2015 market and 2010 market tops.
Also, when HSI touched the bottom part of the channel, it has almost perfectly called market bottoms where relevant. The only false positive here is 2011, where it never reached the bottom of the channel before heading back towards the top.
If you were to literally employ a strategy of LONG SPX until HSI hits the pink line, then short HSI until it his the bottom pink channel, you would have had insane returns. Obviously hindsight, but lets see if this doesn't still work.