Sizzle Index. Sizzle Index is a thinkorswim feature that allows you to find stock symbols that currently see an increase in the number of options traded compared to the last five days’ average.It is calculated as the ratio of the current total volume of put and call options to the arithmetic mean of daily put and call volumes over the last five days. This is not an offer or solicitation in any jurisdiction where we are not authorized to do business or where such offer or solicitation would be contrary to the local laws and regulations of that jurisdiction, including, but not limited to persons residing in Australia, Canada, Hong Kong, Japan, Saudi Arabia, Singapore, UK, and the countries of the European Union. With thinkorswim you get access to elite-level trading tools and a platform backed by insights, education, and a dedicated trade desk. Experience the unparalleled power of a fully customizable trading experience, designed to help you nail even the most complex strategies and techniques.