A retail trader marks yesterday's high. A desk trader marks that too, and also the weekly open, the monthly open, and last week's close, because larger accounts plan around longer horizons and those levels are where their bigger decisions get made. You do not need institutional size to use institutional reference points; you just need to know they exist and that a meaningful slice of the volume moving EURUSD, gold and the indices is watching the same handful of numbers you can mark for free.
The weekly open as a bias line
The weekly open is simply the first price of the trading week, typically Sunday evening into Monday in New York time. Many desks use it as a rough dividing line for the week's bias: price trading above the weekly open through Tuesday and Wednesday suggests the week is bullish so far, and pullbacks toward that open are often treated as buying opportunities rather than reasons to turn bearish. The level matters less as a precise trigger and more as a running scoreboard: is the week net positive or net negative relative to where it started, and does the current pullback or rally still respect that framing.
Monthly opens and the bigger picture
The monthly open works the same way at a coarser scale and matters most for instruments with real macro drivers, gold especially. Gold opening a month at 2,380 and spending three weeks above that price is telling a simple story: buyers have controlled the month so far. A sharp pullback in week three that holds above the monthly open often gets treated very differently than the same pullback breaking clean through it, because breaking the monthly open changes the entire month's story from controlled uptrend to something closer to distribution. Intraday traders do not need to trade off the monthly open directly, but knowing which side of it price sits on adds real context to an otherwise ordinary daily setup.
Last week's close and the weekend gap
Forex trades continuously from Sunday evening to Friday evening, but the weekend still leaves a mark: last week's close is the reference for whether Monday's open represents a gap. A small gap, a few pips on EURUSD, is unremarkable. A larger gap, the kind that shows up occasionally around a surprise weekend headline, tends to get at least partially filled as the week progresses, because the price levels traded heavily in the days before the gap still represent real value that the market often revisits. This is not a rule to trade mechanically, but it is a genuine tendency worth knowing before assuming a Monday gap is simply the new normal.
Using these levels without overcomplicating the chart
The point of these reference lines is not to add five more things to watch. It is to explain, in one glance, why price might be behaving differently around an ordinary daily level than it did last time. A EURUSD daily support at 1.0810 that also happens to sit right at the weekly open carries more weight than the same level with no institutional reference nearby, because more participants have a reason to defend it. Mark the weekly open every Sunday night, the monthly open on the first trading day of the month, and last week's close alongside it, and leave everything else off the chart. Three extra lines, checked once a week and once a month respectively, is enough to see when an ordinary level is quietly doing extra work.