One reason to use the secondary currency in a company is to report on both your primary currency and your secondary currency.
Say you have a company in Canada that does transactions in both US Dollars and Canadian Dollars. If your master currency is set to USD your ledger transactions will have the USD equivalent in the AmountMST field and the amount in the transaction currency in the AmountCur field. For transactions that are in CAD then will have both the USD and CAD values, but for transactions in USD both fields will be in USD. Setting your secondary currency in the company to CAD means that all transactions will have the USD amount in AmountMST and the CAD amount in AmountMSTSecond.
|Currency Code||Master currency amount||Transactional currency amount||Secondary/Reporting currency amount|
|USD||$100 USD||$100 USD||$98 CAD|
|CAD||$100 USD||$98 CAD||$98 CAD|