Whats that SWAP thing

Hi,
I trade a little and still wonder who pays SWAP when my is something positive,
Who gets it in oposite situation

How can I predict is it gona be + or -

When is it change [beggining of a day?, midnight of some unknown timezone?]

thx a looot

SWAP is just the interest rate differential for the pair. It changes when interest rates change.

Example:
EUR/USD

You go long, you sell off borrowed USD and buy EUR. You're pay interest on the USD you've borrowed and will be paid interest on the EUR. Because the EUR has a higher rate than the USD right now that amount will be positive. It's paid for, at some point (in theory) by people that are short the euro and paying it's interest rate.

Briliant! that's what my intuition said
Thanks a lot for help!