The babypips.com school has a section that reads that you pay the spread only once. If you go long, you pay when you enter the position. If you go short, you pay when you leave the position.
If that is true, then following should also be true:
- A spread is created by moving the the ASK price, leaving the BID price at true market value. Which would support the following two examples:
a) If you hold a long position, and a news release causes the spreads to increase, your p/l will not change because you have already paid the spread.
b) If you hold a short position, and a news release causes the spreads to increase, your p/l will change because you have not already paid the spread.
If anyone can further confirm or give more information on this, please chime in.