Correlation indicates the relation between two mutually dependent variables at a certain time. In the forex world, it means how two currency pairs statistically move either in the same direction or in the opposite. Therefore correlation values can be either in positive or in negative between 0 to 1.
Correlation value can be calculated for any two securities, not necessarily only between currency pairs. Example, AUDUSD vs Gold
Use of currency correlation in trading:
Correlation values are widely used in different kinds of trading, including hedging (explained later).
Suppose, if EURUSD vs USDCAD has a correlation value of 0.70 for the last 5 minutes. Then this can be denoted as 70% positively. Therefore, if during these time USDCAD moves 10 pips then EURUSD also has moved 7 pips (70% of 10 pips).
Hedging means having a buy and sell trade all together on the same securities or multiple securities that are correlated with each other and aggregating the total position value for profits or reducing the loss.
Hedging can be done by opening trade on the same currency pairs at the same price or different prices also in combination with other correlated currency pairs. Sometimes, hedging is used to fix the amount of loss (ignoring the swap charges)
Suppose a trader opened a buy and sell order at 1.2510. That means no matter what direction market moves, both buy and sell orders are hedged. The trader will see the commission or spread cost and swap fees. (One swap fee will be positive and one will be negative)
For loss reduction:
Suppose a trader has an open position at 1.2550 buy order is currently at 20 pips loss as the market has fallen to 1.2530. So If he has not set any stop-loss he could just open a sell order at 1.2530. It will hedge the position with 20 pips maximum loss.
One of the popular trading strategies among traders where they open multiple orders in different correlated currency pairs for hedging the overall position.
In this way, the overall position will be less risky and will generate a stable profit.
The term basket is used here because orders are placed with one single base currency and its combination with other currencies. Below is an example with GBP basket:
Total: $3.23 profit
EURGBP was in sell position due to EUR negative correlation with GBP.