Thread by @compudex

Delta: again so complex definition but simplest way to treat delta as Probability % of option to be IN THE Money at expiry. You can sumup the Probability of Call and Put both.

When you buy stock in cash, it's delta is 1. It's ITM already, 😀

If you buy ATM Call, it's delta is 50%, have you noticed that? The Probability of ATM becomes ITM is 50%, underlying may go up or go down or remain there.

If stock moves 1rs, call value moves 0.50rs, delta is 50

Sbi with 36% implied (writer expected) volatility, in 4 days to expire. Chances (Probability) are 27% for 310 call reaching ITM.

19% Probability to end up underlying below 290, so put 290 delta is 19 (-ve sign to represent put/bearish)

So if I sell 310ce and 290 put, Probability of me making loss (having either one in ITM) is sum of delta value which 46%

Total premium 1.35+2.15=3.50rs for taking unlimited risk with Probability of 46% loss and 54% profit in 4 days. That's what writer does. Ps: I'm retailer and not Pro. Learnt by experience and reading.

And here is mathematical formula or bookish language to define delta, which I never understand. 😁😀

If you're holding 500 Reliance, it's 500 positive delta, I would prefer to sell 15 delta call which is 1000(lot size) *0.15 delta (bearish) every month and take the premium for reliance not moving above that level. Time pays you.

Sept expiry reliance 1400 call is having delta 15, so probability of reliance closing above 1400 at Sept expiry is 15%, if I'm holding reliance in cash, I would sell 1400CALL and make time value pays me. That's called "covered call" as by pro/book language