I went to a website and checked values of 11800 CE sell sept. 18 expiry and I found following values
Theta = 262.10
delta = -21.56
Vega = -651.22
Gamma = =0.08
Please note accept theta each value is negative …
Theta of 262.10 value means total decay until expiry …It has to be because it can decrease at such level per day?