The majority of the volume in currency trading is confined to only 18 currency pairs compared to the thousands of stocks that are available in the global equity markets. Although there are other traded pairs outside of the 18, the eight currencies most often traded are the U.S. dollar (USD), Canadian dollar (CAD), euro (EUR), British pound (GBP), Swiss franc (CHF), New Zealand dollar (NZD), Australian dollar (AUD) and the Japanese yen (JPY). Although nobody would say that currency trading is easy, having far fewer trading options makes trade and portfolio management an easier task.
The currency exchange rate is the rate at which one currency can be exchanged for another. It is always quoted in pairs like the EUR/USD (the Euro and the US Dollar). Exchange rates fluctuate based on economic factors like inflation, industrial production and geopolitical events. These factors will influence whether you buy or sell a currency pair.
Multiple Currency Pairs - Similarly we need to support the major currency pairs beyond "Cable" (GBP/USD). There are two aspects to this. The first is to correctly handle the calculations when neither the base or quote of a currency pair is equal to the account denomination currency. The second aspect is to support multiple positions so that we can trade a portfolio of currency pairs.
The script is currently hardcoded to generate forex data for the entire month of January 2014. It uses the Python calendar library in order to ascertain business days (although I haven't excluded holidays yet) and then generates a set of files of the form BBBQQQ_YYYYMMDD.csv, where BBBQQQ will be the specified currency pair (e.g. GBPUSD) and YYYYMMDD is the specified date (e.g. 20140112).
Each time you open a new trade, calculate how much free margin you would need to use if the trade drops to its stop loss level. In other words, if your free margin is currently $500, but your potential losses of a trade are $700 (if the trade hits stop loss), you could be in trouble. In these situations, either close some of your open positions, or decrease your position sizes in order to free up additional free margin.
Forex margin is a good faith deposit that a trader puts up as collateral to initiate a trade. Essentially, it is the minimum amount that a trader needs in the trading account to open a new position. This is usually communicated as a percentage of the notional value (trade size) of the forex trade. The difference between the deposit and the full value of the trade is “borrowed” from the broker.
The script is currently hardcoded to generate forex data for the entire month of January 2014. It uses the Python calendar library in order to ascertain business days (although I haven't excluded holidays yet) and then generates a set of files of the form BBBQQQ_YYYYMMDD.csv, where BBBQQQ will be the specified currency pair (e.g. GBPUSD) and YYYYMMDD is the specified date (e.g. 20140112).
Forex margin is a good faith deposit that a trader puts up as collateral to initiate a trade. Essentially, it is the minimum amount that a trader needs in the trading account to open a new position. This is usually communicated as a percentage of the notional value (trade size) of the forex trade. The difference between the deposit and the full value of the trade is “borrowed” from the broker.

Now that we have discussed the longer term plan I want to present some of the changes I have made to the code since diary entry #2. In particular, I want to describe how I modified the code to handle the Decimal data-type instead of using floating point storage. This is an extremely important change as floating point representations are a substantial source of long-term error in portfolio and order management systems.
The majority of the volume in currency trading is confined to only 18 currency pairs compared to the thousands of stocks that are available in the global equity markets. Although there are other traded pairs outside of the 18, the eight currencies most often traded are the U.S. dollar (USD), Canadian dollar (CAD), euro (EUR), British pound (GBP), Swiss franc (CHF), New Zealand dollar (NZD), Australian dollar (AUD) and the Japanese yen (JPY). Although nobody would say that currency trading is easy, having far fewer trading options makes trade and portfolio management an easier task.
Unit Tests for Position/Portfolio - While I've not mentioned it directly in diary entries #1 and #2, I've actually been writing some unit tests for the Portfolio and Position objects. Since these are so crucial to the calculations of the strategy, one must be extremely confident that they perform as expected. An additional benefit of such tests is that they allow the underlying calculation to be modified, such that if all tests still pass, we can be confident that the overall system will continue to behave as expected.
As you may now come to understand, FX margins are one of the key aspects of Forex trading that must not be overlooked, as they can potentially lead to unpleasant outcomes. In order to avoid them, you should understand the theory concerning margins, margin levels and margin calls, and apply your trading experience to create a viable Forex strategy. Indeed a well developed approach will undoubtedly lead you to trading success in the end.
We use real-time margining to allow you to see your trading risk at any moment of the day. Our real-time margin system applies margin requirements throughout the day to new trades and trades already on the books and enforces initial margin requirements at the end of the day, with real-time liquidation of positions instead of delayed margin calls. This system allows us to maintain our low commissions because we do not have to spread the cost of credit losses to customers in the form of higher costs.
Trading on a margin can have varying consequences. It can influence your trading experience both positively and negatively, with both profits and losses potentially being seriously augmented. Your broker takes your margin deposit and then pools it with someone else's margin Forex deposits. Brokers do this in order to be able to place trades within the whole interbank network.
As we've already stated, trading on margin is trading on money borrowed from your broker. Each time you open a trade on margin, your broker automatically allocates the required margin from your existing funds in the trading account in order to back the margin trade. The precise amount of allocated funds depends on the leverage ratio used on your account.
Maintenance margin for commodities is the amount that you must maintain in your account to support the futures contract and represents the lowest level to which your account can drop before you must deposit additional funds. Commodities positions are marked to market daily, with your account adjusted for any profit or loss that occurs. Because the price of underlying commodities fluctuates, it is possible that the value of the commodity may decline to the point at which your account balance falls below the required maintenance margin. If this happens, brokers typically make a margin call, which means you must deposit additional funds to meet the margin requirement.

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