The swap of certain products relates to the postponed new value date of underlying futures contracts due to weekends.
Typically, the settlement of foreign exchange transactions is settled on T+2 (Settlement date of foreign exchange markets is two days from when the position was held pass through EOD.)
For instance, when the investors open the positions and hold them past Monday, they will be "rolled over" to Tuesday and settled as one trading day from Wednesday over Thursday. Similarly, when the investors open the positions and hold them past Wednesday, they will be "rolled over" to Thursday and settled as one trading day from Friday to Saturday.
However, the international financial markets close on weekends. In this case, the actual settlement will be calculated as 3-days because the new value date is Monday instead of the weekend.
What's more, precious metals are generally regarded as safe-haven currencies. For this reason, holding positions of gold or silver past Wednesday will be counted in a 3-days swap as keeping the forex currency pairs positions.
Oil, indices, commodities, and shares are settled on T+0. When the investors hold these mentioned kinds of products over Friday, the swap will be calculated as 3-days as well.
Kindly be reminded: The trading session of certain products opens 7days/week. Due to the displaying limits of the contract specification of spot contracts on MetaQuote software, from Nov. 08, 2021, the 3-days swap in contract specification will still be Friday. However, the swap of holding positions over Friday will not be calculated as 3-days. It will be calculated on Saturday and Sunday, respectively.