WILLIAMS %R - 1966. Inspired by Allan C Davis. This may well be the most widely followed index in the marketplace, as it is shown every day in China on every stock in their markets. A great tool with many uses.
PROJECTED HIGHS AND LOWS, A.K.A. PIVOT POINTS - 1966. These are wildly popular nowadays. I first wrote about them in my 1966 book on the stock market. I know they're good, I learned them from Owen Taylor's work in the 1930s... but they are not the "be all end all" that people who sell this formula claim. Be careful if you use them.
WILLIAMS ACCUMULATION/DISTRIBUTION - 1967. I think the first book I ever read about the stock market was Joe Granville's, and I was taken by his on balance volume idea. There are things I liked about it a great deal and eventually I found the two gentlemen from San Francisco Woods and Vignolia who were apparently the originators of the concept. But there were problems with OBV. Dave Bostian had his intra-day intensity index, which triggered an idea in my mind to reference the opening price to measure accumulation and distribution. We hand punched computer cards, loaded them into the computer and came up with a new way of measuring accumulation distribution that I still use to this very day. This was a major breakthrough.
SHADOW TECHNIQUE FOR MOVING AVERAGES - 1969. Later on, this became known as projected moving averages. It is just one more way of smoothing out the trend of a moving average and knowing when a real trend change has taken place. Prior to my work though, no one was leading or lagging moving averages.
MOMENTUM STUDIES OF ACCUMULATION - 1970. Once we had a new way of looking at accumulation distribution (Williams Accumulation/Distribution), Jim Waters, one of my stockbrokers, and I began measuring the momentum of the accumulation. We first wrote about this in Commodities Magazine in 1970. It has since been written about by many people, but again, our work was the first.
WILLGO - 1970. This indicator was first discussed in my 1970 book. It is a measure of municipal bond prices to forecast stock market turns. While not always perfect, it has held up over the years in giving a reliable forecast of were stock prices are going.
FOUR YEAR MASTER STOCK MARKET PATTERN - 1970. I made my first million dollars trading stocks in 1970. However, I did not cover my short sales soon enough and gave back a good deal of profits on the rally off the low. Late one night, licking my wounds and looking at my charts, I noticed a particular pattern, revolving around the last four years. Nothing has done a better job of calling future market turns than this pattern I discovered... that's right, nothing.