Nice historical volatility chart
This is a helpful annotated chart of yearly S&P 500 volatility. I bookmarked it back in 2014, so it only covers the years from 1929 to 2014.
S&P 500 calendar year realized volatility from 1929-2014 $SPY $SPX $VIX
— via Ro_Patel on StockTwits, October 09, 2014
The y-axis is S&P Calendar Year Realized Volatility as a percentage. The x-axis is time in years. I hope it is possible to enlarge the image by clicking on it! The red bars represent the 10 years with highest volatility. The green bars represent the 10 years with the lowest volatility. I am guessing that the blue bars are all other years.
I wondered why the chart was tagged with $SPY $SPX and $VIX. Both StockTwits and Twitter used to denote stock symbols with a dollar sign instead of a hash tag.
The first two were easy. SPY is an ETF that is backed by actual shares of stock in the companies that are included in Standard & Poor's 500 index. SPX is driven by the price of the S&P 500 Index itself. SPX isn't tradeable per se, but there are SPX futures and various SPX options.
Volatility and the fear indicator
Volatility is the standard deviation of a stock, stock index, or other security's annualized returns over a time period; essentially, the rate at which the security or index price increases or decreases. ‘Actual’ (historical) volatility measures the variability of known prices.
What is $VIX
VIX is called the fear indicator because it is used to infer a quantitative metric of market risk, fear, and stress. It is defined as the 30-day expected volatility of the S&P 500 stock index, using Chicago Board Options Exchange (CBOE) listed S&P 500 options data. VIX is a measure of implied volatility (forward-looking) not historical. Values over 30 are considered high, while 20 is more typical. There's no upper bound on VIX.
The VIX isn't tradeable, which is why I am amused that its CBOE landing page (URL above) has "tradeable" in the URL! Instead, there are VIX futures, call and put options for trading.
The VIX was introduced by CBOE in 1993. I think that's why this chart doesn't have VIX on the y-axis (only alluding to it with $VIX) as an historical time series. It wouldn't be possible to impute historical values, especially not to 1929 but not even prior to 1993, because VIX is calculated by aggregating weighted prices of a constantly changing portfolio of S&P 500 calls and puts over a range of strike prices.
StockTwits
StockTwits seems mostly moribund to me, since about 2015. The name is a little strange, but it is a great idea: A social network for investor/speculators. The realtime, Twitter-like functionality, and user interface, are well-designed and fun. I think StockTwits was founded by Howard Lindzon who is nice, and maybe Fred Wilson the AVC guy ("A Venture Capitalist"?). EDIT: I just checked. It is still active but not exactly a huge startup venture.
Now that Amazon.com has retired Alexa, I can't find website metrics as easily. I'm mildly curious about StockTwits. I wish I could average unique annual page views per year, and then do a 3-line time series graph of unique daily views during 2012 (when it was really active), 2015, and last year.
