Gyroscopic Investing

When analyzing portfolios, the concept of "Drawdown" is often used, and expressed as a percentage.

I was wondering if anybody has data on drawdowns measured in Days?

e.g. on Feb 09 2018, the S&P 500 experienced an intraday low of 2533, from a Jan 26 high of 2873: that's a drawdown of ~12%.

But looking at it from another perspective, the last time someone could have bought the index at 2533 was on Oct 04 2017. This particular 12% drop caused the index to "undo" 128 days of gains, for anybody who had been invested 128 days or longer.

On March 6, 2009, the index "undid" 13 years of gains, all the way back to September 1996.

Does anybody have a nice chart that shows historical drawdowns measured in this manner?

Generate drawdown charts for any portfolio at portfoliovisualizer.com

I like your "days lost" concept, although it's a little tricky to calculate. Aside from the very granular data, there's also the issue of not having enough data to look back far enough to measure the lost gains for a large early loss. For example, in 1974 US stocks fell 49% off of their 1972 highs. But since stocks only rose 21% from 1970-1972 I can't look back far enough to know how many years of gains that wiped out.

In any case, I have annual drawdowns data for any portfolio since 1970 measured in depth, length, and a hybrid Ulcer index if you're interested.

https://portfoliocharts.com/portfolio/drawdowns/

portfolio charts shows "Years To Recover" which is useful if you're trying to gain an intuitive grasp for the risk of having to cash out at depressed prices due to a financial commitment at a known future date.

However I would really like to see "Years of Gains Undone" as I believe that could provide an intuitive grasp for the opportunity (upside risk) of being able to buy lower later when you can't or won't participate in a currently ongoing bull market.

"Years To Recover" is a sneaky form of bullish cheer-leading, which tells you to get in the market NOW because if it goes down, it'll recover within a long enough timeframe.

"Years of Gains Undone" would be a bearish-leaning, as I suspect this measure would show there should never be any hurry to get in, since you can buy cheaper within a long enough timeframe.