Forex - Does initial currency invested matter?

External question — Personal Finance Stack Exchange Author: CatsLoveJazz Original post: https://money.stackexchange.com/questions/49605 License: CC BY-SA 3.0 — https://creativecommons.org/licenses/by-sa/3.0/ Adaptation: HTML converted to plain text; contact email addresses removed. My question is around the base currency and what bearing, if any, this has on the to the initial currency you invest when opening a trading account. For example, I live in the UK so I open an account with a broker with £10k GBP of capital. It's clear to me how I can then trade on say GBP/USD where I am buying USD with my initially invested GBP. How does this work in the case I want to trade EUR/USD? Or, if I decide to open a short position with a GBP/USD pair (buying GBP with USD)? Thanks