When I read your initial question, my first guess was that this might be about buying options before earnings announcements and the losses due to implied volatility contraction after the EA.
My second guess was that this might be about how put premium inflates before a pending dividend. With the data that you posted in your comment, these were bad guesses since (1) there's no dividend on AMD and (2) you posted the Greeks so it's clear that you have more than a noob's understanding of options.
There are three variables in play here:
- Time decay
- AMD's price change
- Change in implied volatility
Modeled, the expectation would be that there would be a loss of 20 cents of premium over 15 days. This is almost borne out by your stats. With a an actual theta of -0.103 (your number is high, perhaps because it was rounded up), you'd expect to get 20 cents of time decay which matches the modeling.
With an average delta of ~ 0.455 across the price range, with a price drop of 45 cents, you'd expect the put to appreciate by the same 20 cents so premium should be unchanged.
But because IV contracted by ~8% (the actual IV declined 4.1), the net effect was a premium decline to $3.70
Here's an online calculator that you can play with. Isolate one variable at a time to measure the effect of the change in premium:
The results of program that I use was pretty close to those of this calculator. Either way, the IV numbers should be in the vicinity of .53 and 49. The IV numbers that you provided appear way too high (72.9 and 63).
Hope this all makes sense.