The major currencies in most people’s estimation are the US dollar (USD), Euro (EUR), yen (JPY), pound (GBP), Swiss frank (CHF), and the Canadian and Australian dollars (CAD and AUD). So there are 6 major pairs where USD is combined with any other of the majors. Cross pairs are those excluding USD, for example CBP/CHF. Generally, if a broker offers any minor currencies for trading, the spread will be high. The exception could be a broker will offer the currency of their own country at cheap rates even if that currency is not a major. This is especially true for secondary currencies like the New Zealand and Singapore greenbacks that are close to making it into the majors vis daily trading volume. First, there’s a lot of competition between brokers so that the spread is mostly lowest for this pair. Second, the high liquidity means that there will probably be less slippage, and you are more likely to get the price that you see on screen. Third, forex reports alerts have a large amount of stories about these currencies so you aren’t so sure to get caught out by astonishing announcements. Robots often use systems that are pair express, i.e. That won’t work so well on any but the commended pairs, so those will be the best currency exchange pairs for an expert counsel.