Quote from swimmus:
If I buy in the money puts, do I stay within a month or two?
If Out of the money puts- how far out?
Those are the 2 big issues to consider for option buying. IV is another, but for simplicity, let's ignore it.
If you are certain of your time frame, go with a shorter month. If not, go with a longer month.
As for which strike to buy, the OTM put will give you a greater percentage gain if NKE drops substantially and conversely, it will be a big loser if it doesn't. The ITM put will do better if there's only a small drop but could lose more, dollar wise, if NKE rises.
All of this would be evident if you had an option graphing program since a picture is worth a 1,000 words :->)
The poor man's way to get an idea of what might happen is to look at an option chain and extrapolate some possibilities. From today's closing quotes:
NKE 108.80
Apr 110p 2.40 - 2.55
Apr 115p 6.20 - 6.40
May 105p 1.25 - 1.35
May 110p 3.10 - 3.30
May 115p 6.40 -6.60
Suppose you bought the May 105p today for 1.35 and NKE dropped 5 pts tomorrow. The 105p is currently 3.8 pts OTM. It would be 1.2 pts ITM after a 5 pt drop. What May put is 1.2 pts ITM today? Yep, the May 110p. So if NKE dropped 5 pts tomorrow, your May 105p would be worth approx 3.10 (+ 1.75). And if it dropped 10 pts, it would be worth 6.40 (+ 5.15)
Suppose it took 28 days for this drop to occur. Then, you'd do the same process but you'd use the Apr put chain to get the expected value (the May puts today have 53 days until expiration and 28 days from now, they'll have 25 days of life which is what the Apr's have today).
So if NKE dropped 5 pts in 4 weeks, your May 105p would be worth approx 2.40 (+ 1.05). And if it dropped 10 pts, it would be worth 6.20 (+ 4.85). And to repeat, this quickie analysis ignores implied volatility changes. For any time periods in between or price change different than option strike intervals, you'll need an option model - eg. spreadsheet, calculator or graphing program.
Clear as mud ??
