here's whats confusing and bewildering about calendar spreads. 1) in calendar spreads, long rear month, short front month is net long vegas. likewise you are short theta. (you gain as time decay occurs, and lose if IV drops). 2) opposite: short rear month, long front, is usually short vegas and long theta. (you lose quickly to time decay and supposedly gain quickly if IV drops) spreads. Answer probably lies here. Whats so fascinating is that in #1, despite being long volatility, you lose the most if you get a big move. Performs similar to being short a straddle. And in #2, you gain the most if you get a big move away from your strike (your NTRI example), despite being short vega. Performs like being long a straddle. But as evidenced in the failure of my 50/50 NTRI (short rear, long front), IV drop does NOT help this position since you need to finish away from the strike. Interestingly enough, #1 performs similarly to long butterfly spreads and short straddles (different risk/reward ratios of course) despite being a long vega strategy... ... Now to review impact of delta and gamma on calendar ... an as to my BIDU position, I'm essentially straddling for March right now ... but won't keep this position on for long. In the end, BIDU wasn't much of a loss though, since I was able to close those short puts at the best part of the day Thursday. If I can get some movement next week on BIDU, I'll do nicely. Need 3 pts up or 6 pts down to breakeven here. Both are extremely likely.