The Sydney session — first of the week, thinnest liquidity

It is Sunday evening and the rest of the market is still asleep. The charts have not moved for two days, and then, a little after eleven at night in Central Europe, the Australian dollar twitches against the US dollar for the first time since Friday. This is the Sydney session waking the week up. The spread that cost almost nothing on Wednesday is now several times wider. The first hour of the trading week behaves nothing like the rest of it, and that single fact catches more beginners off guard than anything.

What the Sydney session actually is

The Sydney session is the informal name for the hours when dealing desks in Australia and New Zealand are active. In Central European time it runs roughly from 22:00 to 07:00, and its defining feature is the calendar. Australia sits closest to the international date line, so while Europe is still in its Sunday evening, Sydney is already starting a Monday morning. That is why the market wakes up here, around 22:00 to 23:00 Central European time on Sunday, after the weekend.

The scale of this session is modest. According to the Bank for International Settlements Triennial Central Bank Survey of 2022, Australia accounts for only about 2 to 3 percent of global currency turnover measured by the location of dealing desks. For comparison, the United Kingdom holds roughly 38 percent, the United States about 19 percent, and Singapore around 9 percent. Sydney is the smallest of the four great centres, and that fact shapes the character of trading throughout its hours.

How it works in practice

The most important consequence of low turnover is liquidity, or rather the lack of it. Liquidity is simply the number of willing buyers and sellers at any given moment. When there are few of them, the gap between the buy price and the sell price, the spread, widens. During the Sydney session a spread on a popular pair can run several times wider than at midday during the London and New York overlap. Every trade therefore costs more, and the risk of slippage on a fill rises.

The second feature is that the session itself splits into two phases. For the first two hours, from roughly 22:00 to midnight Central European time, Sydney works alone, without the support of another large centre. This is the quietest moment of the entire trading day, when moves can be erratic and a small order can push the price further than the situation would justify. Only around midnight does Tokyo join in, and from that point, roughly between 00:00 and 07:00 Central European time, liquidity improves and quotes become more orderly.

The Sunday open and gap risk

This is the point that matters most to a beginner. The spot currency market is closed all weekend, but the world does not stop. Elections, central-bank decisions outside the normal calendar, military action, or a sudden political crisis can all happen on a Saturday or a Sunday. When Sydney opens the week, the price often starts from a level clearly different from the Friday close. We call this a price gap, and it is an inherent part of the market's weekly cycle of opens and closes.

A gap is a real threat to protective orders. If you leave a position over the weekend with a stop loss, and the price opens on Sunday on the other side of that order, your broker will fill it only at the open, that is, at a price far worse than you intended. The classic example is the Brexit referendum of June 2016, when the British pound opened the new week several hundred pips below its Friday close. I cover the mechanics of the gap and the ways to defend against it in more detail in the piece on weekend trading and Sunday gap risk.

„The Australian session is the quietest of the trading day, and the pairs that become most active in it are those involving the Australian and New Zealand dollars." — Kathy Lien, Day Trading and Swing Trading the Currency Market, Wiley, 2016.

Which pairs come alive in Sydney hours

The session has its natural pairs, the ones in which one side is a regional currency. These are above all the Australian dollar and the New Zealand dollar. In practice the most happens on AUD/USD and NZD/USD, and during the overlap with Tokyo, AUD/JPY joins them. These are the instruments with the tightest spread and the most sensible moves at this time, because they are traded by participants for whom it is a local working day.

The typically European pairs — EUR/USD, GBP/USD, or USD/CHF — are quiet during the Sydney session, and their spread tends to be disproportionately wide relative to the negligible movement. Trading them actively at this hour usually means paying high costs for a small chance of profit. If you are specifically interested in the regional currencies and how they react to data out of China, I expand on that in the piece on the Tokyo session and yen pairs, because the two sessions work together for several hours.

The data that moves this session

Although Sydney is quiet, it has its own events that can stir it. The Reserve Bank of Australia, the country's central bank, usually announces interest-rate decisions on Tuesday around 05:30 Central European time, and that is a moment when the Australian dollar can move sharply. The second key point is data out of China, often published around 02:45 Central European time, already during the overlap with Tokyo. China is Australia's largest trading partner, so a weaker or stronger reading from Beijing feeds directly into the Australian dollar.

For someone trading from Europe, both of these hours fall in the middle of the night. That does not mean you have to sleep through them defenceless. It lets you plan pending orders in advance and set alerts, rather than making half-awake decisions the moment you wake. The same approach is worth applying to the whole cycle of sessions, which forms a chain of Sydney, Tokyo, London, and New York; I lay it out in the overview of the three main forex trading sessions.

The most common misunderstandings

The first misunderstanding goes like this: since the market is open, you can trade any minute the same way. That is not true. The low-liquidity hours have a different mechanic and they punish carelessness with a wide spread and slippage. The second misunderstanding is the belief that the Sunday open is an opportunity because „everyone is asleep". In reality it is a moment of heightened risk, not of edge — the first hour of the week tends to be erratic and expensive.

The third mistake is treating the Sydney session as a separate strategy. For the vast majority of people trading from Europe this is not a time for active trading, but a part of the day worth understanding so that you can control the risk of positions held over the weekend. Sydney matters not because you trade in it, but because it sets the starting point for the entire week.

What to do tomorrow

1. Check the opening hours at your broker. Open the instrument specification on your platform and write down the exact time of the Sunday open and the Friday close in your local time. Brokers differ by tens of minutes, and around the switch from summer to winter time the window shifts by an hour — without that figure you cannot consciously plan any position that straddles the weekend.
2. Compare the spread at two times of day. Next Sunday around 23:00 note the spread on AUD/USD, then do the same on Wednesday afternoon during the London and New York overlap. You will see for yourself how much trading costs in the lowest-liquidity hours, and you will stop treating Sunday evening as an ordinary time of day.
3. Set a rule for weekend positions. Before you shut the computer on Friday, decide deliberately: either you close the position before the market closes, or you leave it with a smaller size and a wider stop loss that can survive a possible Sunday gap. Write that rule into your trading journal and stick to it for the coming month, instead of deciding under the pressure of emotion.