In the solution for this question it says" long calls have positive deltas". Could this imply that short calls have negative deltas?
I would think it’s still positive, despite the fact that you lose money if the stock goes up. As stock moves up, the option premium does too, regardless of whether your long or short, whereas a put premium moves down as price moves up (neg delta).
I believe all call options are pos delta and all puts neg delta, but could be wrong… just thinking through this logically without consulting the curriculum so someone feel free to correct me.
Your question is ambiguous. A call option always has long delta. A short call position thus has short delta (you have a negative position in a long delta option).
ohai,
thanks for input but I still don’t get it… 
it was my understanding that delta for calls ( long and short) is between 0 and 1.
from what you say, actually we could have a negative delta if you are short a call. please correct me if I am wrong…
Err… ok. Think of it like this. A stock (just normal equity) has delta of 1. If you disagree, convince yourself that this is true.
The delta of 1 does not change depending on whether you buy or short the stock. The *stock* always has a delta of 1.
Now, what happens if you *short* the stock? You have a negative position in the stock, so obviously, your *position* is short delta. However, the stock itself is long delta. The stock and your position are not the same thing.
Similarly, for options, the option itself is not the same as your position in the option.
Call option - always pos delta
put option - always neg delta
Being short doesn’t change the delta. As far as i know at least.
Sign of the delta itself doesn’t change between writer and buyer . But if you’re short you would do the opposite of what the long would do i terms of hedging . So as the writer, you’re effectively negative delta on calls.
A call option delta is always b/w 0 and 1, your position in the option does not change the delta.
by shorting the options you would have theoretically negitive contracts you are holding. for example: if you short 300 call contracts on ABC stock, you would have a position of -300 calls. You then want to find out how your total value is affected by the price of the underlying. this would be found by multiplying your position by the delta (say .5):
-300 calls*(price) * .5
Your delta is still .5 no matter the position you take, whether THAT part is positive or negative matters.
so call delta is always positive but the position in a short call is negative…
thanks everyone !