Together with the wholesale electricity markets of the Czech Republic, Slovakia and Romania, the Hungarian day-ahead market is part of the so-called 4MC market coupling. In this coupled market, Romania plays a special role: while from the Slovakian direction, we mainly import, the direction of the Romanian trade is varying: in 60% of the hours, we export, and in 40%, we import electricity. This also means that the price effect of the foreign trade with Romania on the Hungarian market changes directions: in the majority of the cases, it increases the prices, but sometimes it has a price decreasing effect.