Here is a report from Nomura compared to the same days market forecast from SpotGamma.com. Notice the “zero gamma” levels are the same in both reports at 2935 in the S&P500.
We call the “zero gamma” level “volatility trigger”. Using this level can help forecast the level of stock market volatility. Under this market price options dealers go from long gamma to short gamma, which changes the way they trade in the market. See here for explanation.
Its important to note you can only get their analysis if you are a large hedge fund or asset manager.