Visit the Mathema Option Pricing System, which supports FX options and structured product pricing and valuation!

The formulas for calculating the bid (BID) and ask (ASK) prices for Currency1/Currency2 depend on how Currency1 and Currency2 are quoted.
The table below summarizes the spot price calculation rules:
Currency1 Quotation | Currency2 Quotation | BID12 | ASK12 |
---|
DIRECT* | DIRECT | qu12×(Ask1Bid2)×(qu2qu1) | qu12×(Bid1Ask2)×(qu2qu1) |
DIRECT | INDIRECT | (Ask1×Ask2)×(qu1×qu2)qu12 | (Bid1×Bid2)×(qu1×qu2)qu12 |
INDIRECT** | DIRECT | qu1×qu2qu12×(Bid1×Bid2) | qu1×qu2qu12×(Ask1×Ask2) |
INDIRECT | INDIRECT | qu12×(Ask2Bid1)×(qu1qu2) | qu12×(Bid2Ask1)×(qu1qu2) |
Here:
Symbol | Meaning |
---|
Bid1 | Bid spot price for Currency1 |
Ask1 | Ask spot price for Currency1 |
Bid2 | Bid spot price for Currency2 |
Ask2 | Ask spot price for Currency2 |
qu12 | Quotation unit of Currency1/Currency2 if present in the style management*; otherwise, 1 is used |
qu1 | Quotation unit of USD/Currency1 if present; otherwise, 1 |
qu2 | Quotation unit of USD/Currency2 if present; otherwise, 1 |
qu1 and qu2 represent the default base currency (Base Currency) as USD.
When a fixed amount of foreign currency (USD) is quoted against a variable amount of domestic currency (JPY), it is called direct quotation.
For example, the USD/JPY exchange rate of 121.91 means:
- 1 USD can be exchanged for 121.91 JPY.
USD is the base currency, and JPY is the quote currency.
When a fixed amount of domestic currency (GBP) is quoted against a variable amount of foreign currency (USD), it is called indirect quotation.
For example, the GBP/USD exchange rate of 1.6870 means:
- 1 GBP can be exchanged for 1.6870 USD.
GBP is the base currency, and USD is the quote currency.
Assume the following quotes to calculate the EUR/GBP price:
Currency Pair | BID | ASK | Quotation Mode |
---|
EUR/USD | 0.9907 | 0.9910 | INDIRECT |
GBP/USD | 1.5592 | 1.5598 | INDIRECT |
Here:
qu12 = 1
qu1 = 1
qu2 = 1
Since both direct currency pairs are INDIRECT:
Direction | Formula | Calculation Process |
---|
Bid | qu12×(Ask2Bid1)×(qu1qu2) | 1×(1.55980.9907)×(11)=0.6351 |
Ask | qu12×(Bid2Ask1)×(qu1qu2) | 1×(1.55920.9910)×(11)=0.6356 |
The rules for calculating forward prices are essentially the same as for spot prices:
Currency1 Quotation | Currency2 Quotation | BidOut12 | AskOut12 |
---|
DIRECT* | DIRECT | qu12×(AskOut1BidOut2)×(qu2qu1) | qu12×(BidOut1AskOut2)×(qu2qu1) |
DIRECT | INDIRECT | (AskOut1×AskOut2)×(qu1×qu2)qu12 | (BidOut1×BidOut2)×(qu1×qu2)qu12 |
INDIRECT** | DIRECT | qu1×qu2qu12×(BidOut1×BidOut2) | qu1×qu2qu12×(AskOut1×AskOut2) |
INDIRECT | INDIRECT | qu12×(AskOut2BidOut1)×(qu1qu2) | qu12×(BidOut2AskOut1)×(qu1qu2) |
Here:
Symbol | Meaning |
---|
BidOut1 | Bid1+SwapRatio1BidSwapPoint1 |
AskOut1 | Ask1+SwapRatio1AskSwapPoint1 |
BidOut2 | Bid2+SwapRatio2BidSwapPoint2 |
AskOut2 | Ask2+SwapRatio2AskSwapPoint2 |
BidSwapPoint1 | Bid Swap Point 1 |
AskSwapPoint1 | Ask Swap Point 1 |
BidSwapPoint2 | Bid Swap Point 2 |
AskSwapPoint2 | Ask Swap Point 2 |
SwapRatio1 | Swap point ratio of USD/Currency1; otherwise, 1 |
SwapRatio2 | Swap point ratio of USD/Currency2; otherwise, 1 |
qu12 | Quotation unit of Currency1/Currency2 |
qu1 | Quotation unit of USD/Currency1 if present; otherwise, 1 |
qu2 | Quotation unit of USD/Currency2 if present; otherwise, 1 |
Currency Pair | BID | ASK | SwapRatio | Quotation Mode |
---|
GBP/USD | 1.6012 | 1.6018 | 10000 | INDIRECT |
USD/JPY | 116.91 | 116.97 | 100 | DIRECT |
GBP/USD SwapPoints | -1.55 | -1.3 | | |
USD/JPY SwapPoints | -0.72 | -0.12 | | |
Calculated spot price:
| Calculation Process | GBP/JPY |
---|
Bid | qu1×qu2qu12×(Bid1×Bid2)=1×11×(1.6012×116.91)=187.196292 | 187.1962 |
Ask | qu1×qu2qu12×(Ask1×Ask2)=1×11×(1.6018×116.97)=187.362546 | 187.3625 |
| Formula | Calculation Process | GBP/JPY Outright |
---|
Bid | qu1×qu2qu12×(BidOut1×BidOut2) | 1×11×(1.601045×116.9028)=187.16664 | 187.16664 |
Ask | qu1×qu2qu12×(AskOut1×AskOut2) | 1×11×(1.60167×116.9688)=187.34541 | 187.34541 |
| Formula | Calculation Process | GBP/JPY Swap Points |
---|
Bid | (BidOut12−Bid12)×SwapRatio12 | =(187.1666434-187.196292)*100=-2.9560 | -2.96485 |
Ask | (AskOut12−Ask12)×AskRatio12 | =(187.3454179-187.362546)*100=-1.7090 | -1.71281 |
For currencies converted to USD (the base currency), forward exchange rates are typically quoted not as absolute rates but as points, which represent deviations from the corresponding spot rate.
These points are called forward points or swap points. The forward cross exchange rate between two non-USD currencies can be quoted as forward points or absolute rates. In the former case, the forward points are called cross swap points. The forward rate corresponding to the exchange rate between two forward dates is called the forward/forward rate. Such rates are usually also quoted as forward points.
Refer to the above section.
Refer to the above section.
| Formula |
---|
Bid | (BidOut12−Bid12)×SwapRatio12 |
Ask | (AskOut12−Ask12)×AskRatio12 |