The stock bubble peak in 2000 marked an unprecedented 128% overshooting of the trend. That was leaps and bounds worse than the price move above the trend in the bubbles of 1901 and 1929.
For most of the 21st century, though, the Federal Reserve has done everything in its power to keep stocks permanently elevated above a regression trendline. Yet today, they’ve pushed it to 133% above trend. If the current S&P 500 resided squarely on the regression, it would be down near 1400 (-57.6% decline).