e.g
SPY closed at 191.92
http://stockcharts.com/h-sc/ui?s=spy
http://finance.yahoo.com/echarts?s=SPY+Interactive#{"range":"10y","allowChartStacking":true}
Long Put:
Buy 1 Jan'17 190 put for 16.33
Price............ Profit / Loss............ ROI %
142.50.............. 3117.00.............. 190.88%
161.19.............. 1247.60................ 76.40%
173.67.................. 0.00................. 0.00%
180.87............... (720.10)............. -44.10%
190.00............... (1633.00)........... -100.00%
200.55............... (1633.00)........... -100.00%
Put Spread:
Buy 1 Jan '17 190 put and Sell 1 Jan '17 170 put for a net debit of 6.95
Price.................. Profit / Loss........... ROI %
127.50................... 1305.00.............. 187.77%
149.07................... 1305.00.............. 187.77%
170.00................... 1305.00.............. 187.77%
171.78................... 1127.00.............. 162.16%
183.05......................... 0.00................. 0.00%
190.00..................... (695.00).......... -100.00%
194.49..................... (695.00).......... -100.00%
217.20..................... (695.00).......... -100.00%
239.90..................... (695.00).......... -100.00%