Standing gaps: why some crypto price gaps never close

Most gaps between two exchanges' prices close within seconds: someone buys where it's cheap and sells where it's dear (crypto arbitrage after fees). Now and then one doesn't. It stays open for minutes, sometimes for days, wide enough to pay after both fees. That's rarely money nobody has noticed: usually something stops traders closing it. Signals marks these gaps Standing, so you look for the reason first.

What is a standing gap?

On Signals, each gap is timed from when the page began reading. Open for says how long, with a + where it was open already then, and on a wide screen a line beside it draws its last ten minutes, a point every ten seconds on spot and every thirty on perpetuals, broken where the gap was shut. Standing marks a gap open after fees the whole ten minutes the line covers; New, one that opened since the page began reading and isn't standing yet.

Nothing is kept between visits, so a gap open for days shows as open since you arrived, and is marked Standing once the page has watched it for ten minutes.

Why do some gaps stay open?

• A dollar that isn't a dollar. An exchange whose customers can't easily move money in or out can run dearer or cheaper than the rest day after day, its dollars worth a little more or less there (crypto exchange premiums). Signals converts prices in USDT, USDC and USDG at Kraken's rates before it compares anything, so a stablecoin's own small premium is taken out (why prices differ); what's left is the market's own.
• Withdrawals or deposits that are slow or shut. If an exchange pauses a coin's withdrawals, nobody can take its cheap coins out to sell elsewhere; if it pauses deposits, nobody can bring coins in to sell at its higher price. Either way its price can drift from everyone else's and stay there.
• A book few trade on. A market that traded under $100K in the last 24 hours is marked Thin: its best price may be a few small orders, and the gap the size of one of them.
• Two issuers of one share. A tokenized stock can be issued by different companies on two exchanges. Both follow the same share, but they're not the same thing to hold or to redeem, so their prices needn't meet: Issuers differ marks the pair (tokenized stocks).
• A company that isn't listed. Some exchanges offer perpetuals on companies that aren't listed on any stock exchange. With no share price to pull two exchanges' prices together, each follows its own market: Pre-IPO marks them.
• Perpetuals, which never expire. Two exchanges' dated futures meet at expiry (the futures spread trade); nothing makes two perpetuals meet. A gap between them is kept only by closing both legs once it narrows, with funding paid or received on each meanwhile. Signals on perpetuals lists them under Perpetuals priced apart, and marks one that stands.

Why mark them rather than hide them?

Because the reason may not apply to you, and because the gap is true: two exchanges disagree on a price. You may already hold coins and dollars on both exchanges, or a coin's withdrawals may be open again. So Signals marks a standing gap rather than leaving it out, as it marks thin markets rather than hiding them, and leaves the judgment to you. It never says which way a price will go.

How do you check one before trading?

1. Open the coin's page: its name on the list is a link. Both order books and each exchange's price are there, and at its foot the notes the site keeps about the market itself, such as whose token it is.
2. Check both exchanges' status pages for the coin's deposits and withdrawals.
3. See how far it goes: Goes to on Signals walks both books for the top ten, and the coin's page shows each book's depth. A standing gap on a thin book may be good for very little.
4. Check what you'd hold: which dollar each side is priced in, and whose token.
5. Check you can use both exchanges where you live.

How it reads on Signals

• On spot, Show, over the list, narrows it to All, New or Standing, and a link opens it on the standing gaps alone.
• Work it out says, under Open for, that a gap has been open the whole ten minutes the line covers, or how many times it has opened since the page began.
• Opened again and again, a card under the list, counts how often each gap has opened after fees since the page began, and for how long in all. Gaps that flicker like that rarely last long enough to take.
• On perpetuals, Perpetuals priced apart marks a standing gap the same way, and Held for says how long a funding spread trade's two exchanges have been the widest pair.

What it leaves out

• What happened before you arrived. Each signal is timed from when the page began reading, and nothing is kept between visits.
• A page in the background. It lets its feeds go after a minute unless the alerts are on; then what happened meanwhile isn't known, and the timing starts again.
• The reason. A flag says a gap has stayed open, not why.

Where to find it

Signals, and the standing gaps alone; Signals on perpetuals for perpetuals. From a coin's page, the Signals button on its status bar opens the list for that coin. The spot scoreboard shows which exchanges usually run dearer than others, on every coin they share. For how a gap is costed, read crypto arbitrage after fees; for perpetuals, funding rate arbitrage.

Not financial advice. Prices move while you read them.