EXTERNAL Cboe® S&P 500 10% Buffered 25 Index Series This document details the calculation methodology of the titled index/benchmark. This document, in conjunction with the Cboe Index Rules and Governance document (available on Cboe’s Governance website), provides a transparent and easily accessible view of the methodology used to calculate the Cboe S&P 500 10% Buffered 25 Index Series (“SP2BF10℠ Index Series”), ticker symbol ‘SP2BF10’. Description of the Market or Economic Reality Measure The Cboe S&P 500 10% Buffered 25 Index Series (the “Indices”) is part of a family of Target Outcome Indices. The Indices are designed to provide target outcome returns to the US domestic stock market. To value the component options that comprise the Monthly index series, a model based valuation is used. The Cboe Model is constructed using an implied volatility surface from listed S&P 500 option prices by applying the spline method for interpolation and the SABR model for extrapolation. The spline interpolation is a form of interpolation where the interpolant is a piecewise-defined function by polynomials. The SABR model is a stochastic volatility model, which attempts to capture the volatility smile in derivatives markets. The name stands for "stochastic alpha, beta, rho", referring to the parameters of the model, introduced by Hagan et.al., as an attempt to model the volatility surface and capture the empirically observed dynamic behavior of the smile. Valuations are then calculated for the options on the roll dates and 4:15 p.m. ET each trading date. The options prices used in the calculation of this index are theoretical values generated using a volatility surface constructed in accordance with the Cboe® European-Style Options Implied Volatility Calculation Methodology, which is available on Cboe’s Governance website. Each series in the index is designed to track the returns of a hypothetical investment that over a period of approximately one year seeks to “buffer protect” against the first 10% of losses due to a decline in the S&P 500 Index while providing participation up to a capped level. The capped level is determined on each annual roll date such that there is a premium set to 1 year Overnight indexed Swap (OIS) rate to enter into the hypothetical investment. The SP2BF10 Index Series does not use contributed input data, and all of the input data is readily available via Cboe’s Index website. The SPBUF10 Index Series is non-significant, as defined by EU Regulation 2016/1011 (“EU Benchmark Regulation” or “EU BMR”). Index Calculations The following describes the methodology for calculating the SP2BF10 Index, including applicable formulas and input data. Under the SP2BF10 Index Series methodology, the roll date is 3 business days before the last business day of the month. Should the third business day before the last business day of the month on an exchange holiday, the roll date is the preceding day. There are 12 monthly series that roll 3 business days before the last business day of each month: • Cboe S&P 500 10% Buffered 25 Jan Index Series (Ticker: SP2BF10J) Cboe S&P 500 10% Buffered 25 Index Series • Cboe S&P 500 10% Buffered 25 Feb Index Series (Ticker: SP2BF10F) • Cboe S&P 500 10% Buffered 25 Mar Index Series (Ticker: SP2BF10M) • Cboe S&P 500 10% Buffered 25 Apr Index Series (Ticker: SP2BF10A) • Cboe S&P 500 10% Buffered 25 May Index Series (Ticker: SP2BF10Y) • Cboe S&P 500 10% Buffered 25 Jun Index Series (Ticker: SP2BF10U) • Cboe S&P 500 10% Buffered 25 Jul Index Series (Ticker: SP2BF10L) • Cboe S&P 500 10% Buffered 25 Aug Index Series (Ticker: SP2BF10G) • Cboe S&P 500 10% Buffered 25 Sep Index Series (Ticker: SP2BF10S) • Cboe S&P 500 10% Buffered 25 Oct Index Series (Ticker: SP2BF10O) • Cboe S&P 500 10% Buffered 25 Nov Index Series (Ticker: SP2BF10N) • Cboe S&P 500 10% Buffered 25 Dec Index Series (Ticker: SP2BF10D) A Buffer Protection Option Strategy is a protection strategy that is generally used in a bear, range- bound, or modest bull market environment. It seeks to provide a buffer of protection against downside losses over a set period of time while still providing the opportunity for growth to a maximum pre-determined level. The Indices are part of the outcome based approach to investing. Outcome based investing encourages targeting a specific defined return or “payoff”, with an allowance for a specific defined risk, at a specific point in time in the future. The strategy seeks to provide similar returns to the S&P500 Index, with lower volatility and downside risks, in most market environments with the exception of when the stock market is rallying. Each Monthly Index series will consist of three Option components whose strike price and expiration date will be set on the Roll Date(i) relative to the closing level of the S&P 500 Index on the Roll Date: • Purchased 1 Call Options with strike = 100% of S&P 500 Index closing price • Written 1 Put Option with strike = 90% of S&P 500 Index closing price • Written 1 Call Option with strike = CapRollDate(i) All Options are European-Style Options based on the S&P 500 Index and have an expiration date that is the next Roll Date for the respective Monthly series. Non-Roll Date Calculations The value of the monthly index series will be calculated as follows for t = 1 (i.e. one day after the Roll Date) until t = Roll Date (i+1) (i.e. until the next Roll Date): On all days except roll dates, the money market balance is obtained by compounding the money market balances at the previous business close at their respective daily rate. The rate used is the 1 year Overnight Indexed Swap(OIS) rate which is a fixed/float interest rate swap where the floating leg is the U.S. fed funds rate.. Page 2 of 8 Cboe S&P 500 10% Buffered 25 Index Series 푁푑푎푦푠 푁푑푎푦푠 푀 = (1 + 푟 × ) 푀 − 퐼푛푑푒푥 × 퐴푐푐푟푢푒푑퐼푛푑푒푥퐹푒푒 × 푡 RollDate(i) 360 푡−1 푡−1 365 − 푁푒푤푂푝푡푖표푛푃표푟푡푓표푙푖표퐶표푠푡푅표푙푙퐷푎푡푒 (1) 퐼푛푑푒푥푡 = 푀푡 + 푂푝푡푖표푛푃표푟푡푓표푙푖표푉푎푙푢푒푡 (2) 퐼푛푑푒푥푅표푙푙퐷푎푡푒(푖)−1 푈푛푖푡푡 = (3) 푆푃푋푅표푙푙퐷푎푡푒(푖)−1 푂푝푡푖표푛푃표푟푡푓표푙푖표푉푎푙푢푒푡 = 푈푛푖푡푡 × (푃푢푟푐ℎ푎푠푒푑퐶푎푙푙푂푝푡푖표푛푡 − 푊푟푖푡푡푒푛푃푢푡푂푝푡푖표푛푡 − 푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푡) (4) where: • RollDate(i) − 1 is the value on one day before the last Roll Date; • 푀푡 and 푀푡−1are the values of the money market account on day t and t-1, respectively; • SPXRollDate(i) is the closing value of the S&P 500 Index on the last Roll Date. • 푃푢푟푐ℎ푎푠푒푑퐶푎푙푙푂푝푡푖표푛푡 is the closing value of the Purchased Call Option on day t from Cboe’s valuation model; • 푊푟푖푡푡푒푛푃푢푡푂푝푡푖표푛푡 is the closing value of the Written Put Option on day t from Cboe’s valuation model; • 푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푡 is the closing value of the Written Call Option on day t from Cboe’s valuation model; • 푟RollDate(i) is the1 year Overnight Indexed Swap(OIS) rate on the last Roll Date; • 퐴푐푐푟푢푒푑퐼푛푑푒푥퐹푒푒 is 0.25%; • 푁푒푤푂푝푡푖표푛푃표푟푡푓표푙푖표퐶표푠푡푅표푙푙퐷푎푡푒 is the value of Vega charges determined on the last roll day, equal to 푁푒푤푂푝푡푖표푛푃표푟푡푓표푙푖표퐶표푠푡푅표푙푙퐷푎푡푒(푖+1) on the first day after roll date (Rollday(i)) and equal to 0 on all days except Rollday(i)+1; and 푁푑푎푦푠 is the number of calendar days between day t and previous trading day. Roll Date Calculations On the subsequent Roll Date of each monthly series, the Option components expire and the index series simultaneously rolls to a new set of Options with the expiration of the Options as of the close on the next Roll Date. 퐼푛푑푒푥푡 = 푀푡 + 푂푝푡푖표푛푃표푟푡푓표푙푖표푉푎푙푢푒푡 (5) 퐼푛푑푒푥푅표푙푙퐷푎푡푒(푖+1)−1 푈푛푖푡푡 = (6) 푆푃푋푅표푙푙퐷푎푡푒(푖+1)−1 푂푝푡푖표푛푃표푟푡푓표푙푖표푉푎푙푢푒푡 = 푈푛푖푡푡 × (푃푢푟푐ℎ푎푠푒푑퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖+1) − 푊푟푖푡푡푒푛푃푢푡푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖+1) − 푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖+1)) (7) On every roll date, the cash is used to pay for final settlement of the options and new options are sold. The net cash balanced available for reinvestment is: Page 3 of 8 Cboe S&P 500 10% Buffered 25 Index Series 푁푑푎푦푠 푁푑푎푦푠 푀 = (1 + 푟 × )푀 − 퐼푛푑푒푥 × 퐴푐푐푟푢푒푑퐼푛푑푒푥퐹푒푒 × + 푡 RollDate(i) 360 푡−1 푡−1 365 푈푛푖푡푡−1 × (푂푝푡푖표푛_푆푒푡푡푙푒) −푈푛푖푡푡 ∗ (푃푢푟푐ℎ푎푠푒푑퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖+1) − 푊푟푖푡푡푒푛푃푢푡푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖+1) − 푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖+1) ) (8) Where: 푂푝푡푖표푛_푆푒푡푡푙푒 = (푀푎푥(0, 푆푃푋푟표푙푙퐷푎푡푒(푖+1) − 푃푢푟푐ℎ푎푠푒푑퐶푎푙푙푂푝푡푖표푛푆푡푟푖푘푒푟표푙푙퐷푎푡푒(푖)) − 푀푎푥 (0, 푆푃푋푟표푙푙퐷푎푡푒(푖+1) − 퐶푎푝푅표푙푙퐷푎푡푒(푖)) − 푀푎푥(0, 푊푟푖푡푡푒푛푃푢푡푂푝푡푖표푛푆푡푟푖푘푒푟표푙푙퐷푎푡푒(푖) − 푆푃푋푟표푙푙퐷푎푡푒(푖+1))) (9) 푁푒푤푂푝푡푖표푛푃표푟푡푓표푙푖표퐶표푠푡푅표푙푙퐷푎푡푒(푖+1) = (푉푒푔푎퐶ℎ푎푟푔푒푃푢푟푐ℎ푎푠푒푑퐶푎푙푙 + 푉푒푔푎퐶ℎ푎푟푔푒푊푟푖푡푡푒푛푃푢푡 + 푉푒푔푎퐶ℎ푎푟푔푒푊푟푖푡푡푒푛퐶푎푙푙) (10) CapRollDate(i) is the strike of the Written Call Option such that the following holds true on the Roll Date: 푉푒푔푎퐴푑푗푢푠푡푒푑푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖) = 1 × (푃푢푟푐ℎ푎푠푒푑퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖) + 푉푒푔푎퐶ℎ푎푟푔푒푃푢푟푐ℎ푎푠푒푑퐶푎푙푙) − 1 × (푊푟푖푡푡푒푛푃푢푡푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖) − 푉푒푔푎퐶ℎ푎푟푔푒푊푟푖푡푡푒푛푃푢푡) − 푆푃푋푅표푙푙퐷푎푡푒(푖) × 푂퐼푆푅푎푡푒 (11) 푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖) = 푉푒푔푎퐴푑푗푢푠푡푒푑푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖) + 푉푒푔푎퐶ℎ푎푟푔푒푊푟푖푡푡푒푛퐶푎푙푙 (12) The value of Vega charges per option will be calculated as the Black & Scholes Vega of each option multiplied by the below Volatility spread. Implied Vol Vol Spread IV ≤ 20% 0.50% 20% < IV ≤ 30% 0.75% 30% < IV ≤ 50% 1.00% 50% < IV 2.00% To determine the strike of the Written Call Option, Cboe uses the Cboe® European-Style Options Implied Volatility Calculation Methodology, which is available on Cboe’s Governance website. The strike level is calculated by equating the Model Price adjusted for the Vega charges to the calculated VegaAdjustedWrittenCallOption price in the section above. For each strike, |(푀표푑푒푙 푃푟푖푐푒푖 − 푉푒푔푎퐶ℎ푎푟푔푒푊푟푖푡푡푒푛퐶푎푙푙푀표푑푒푙푖) − 푉푒푔푎퐴푑푗푢푠푡푒푑푊푟푖푡푡푒푛퐶푎푙푙푂푝푡푖표푛푅표푙푙퐷푎푡푒(푖)| < 푇표푙푒푟푎푛푐푒 (13) Page 4 of 8 Cboe S&P 500 10% Buffered 25 Index Series Where: • 푇표푙푒푟푎푛푐푒 = 0.01 Calculation and Dissemination Cboe compiles, calculates, maintains, and disseminates all SP2BF10 Index Series values. The SP2BF10 Index Series is calculated and disseminated as a daily closing index value disseminated following the close of U.S. trading hours. Judgement and Potential Limitations in Calculation No expert judgement or discretion is used by Cboe in performing the calculation of the SP2BF10 Index Series.