The broker basically resets the positions and provides either a credit or debit for the interest rate differential between the two currencies in the pairs being held. The trade carries on and the trader doesn't need to deliver or settle the transaction. When the trade is closed the trader realizes their profit or loss based on their original transaction price and the price they closed the trade at. The rollover credits or debits could either add to this gain or detract from it.
High Risk Investment Notice: Trading Forex/CFDs on margin carries a high level of risk and may not be suitable for all investors. The products are intended for retail, professional, and eligible counterparty clients. Retail clients who maintain account(s) with Forex Capital Markets Limited ("FXCM LTD") could sustain a total loss of deposited funds but are not subject to subsequent payment obligations beyond the deposited funds but professional clients and eligible counterparty clients could sustain losses in excess of deposits. Prior to trading any products offered by FXCM LTD, inclusive of all EU branches, any affiliates of aforementioned firms, or other firms within the FXCM group of companies [collectively the "FXCM Group"], carefully consider your financial situation and experience level. The FXCM Group may provide general commentary, which is not intended as investment advice and must not be construed as such. Seek advice from a separate financial advisor. The FXCM Group assumes no liability for errors, inaccuracies or omissions; does not warrant the accuracy, completeness of information, text, graphics, links or other items contained within these materials. Read and understand the Terms and Conditions on the FXCM Group's websites prior to taking further action.
Governments / Central banks – A country’s central bank can play an important role in the foreign exchange markets. They can cause an increase or decrease in the value of their nation’s currency by trying to control money supply, inflation, and (or) interest rates. They can use their substantial foreign exchange reserves to try and stabilize the market.