The change in probability was due to the move from $545.99 (when you bought the option) to the close of $537.02. Time decay/Theta does not exist. It is a derivative of price that expresses the decline in probabilities/optionality over time.
Oh I see why the probability went from 16-18% all the way down to 1%-2%, you inputted the wrong closing price. GOOGL did not close at $537.02, it closed at $544.86 - that's a big $7.84 (1.4%) error. I bought when GOOGL was at $545.99 and within 19 minutes it dropped to a low of $543.58 then closed at $544.86 - only a $2.41 range.
see, wtf am I missing here - because if I look on Google finance I show the $537.xx close; yet my chart shows $544.80 (last bid). That's why I wrote my original close of being less than $551.86, so call it below $552. Whatever, either way you will lose if expecting a close ITM at expiration.
My apologies. I was quoting from GOOG the C shares. You were doing GOOGL the A shares. Probabilities are a better 6-8%. Price action looks promising. It could happen. Looks like you picked it up as people were selling into your bid. Essentially, you picked up a nickel option (compared to sub-100 stocks, a relative impossibility in retail) with 8.5 delta. Good Luck.
I'd like to see more of these picks. OTM just might be a gamma buying savant. That's a 20 lot for illustration. The gamma explosion from this trade peaks at where I would make a technical exit or expect assignment.
update this thread again after April 10 -- good or bad...so we can see the results (and learn). May the farce be with you
GOOGL at $548.84. April10 557.50 Calls at $0.40 (bid). 2 days to expiration. Trade still open. I have submitted a Limit Order to sell at $2.50, good until April 10 Friday.