Oracles and market hours

The narrative is on oracles and market hours. This page is the decision procedure and the clock arithmetic behind them.

Adapter status

Each price feed sits behind a ChainlinkFeedAdapter. Its status() checks, in this order, and returns at the first match (ChainlinkFeedAdapter):

Where the age of the answer is

$$\text{age} = \max(t_{\text{now}} - \text{updatedAt},\ 0)$$

(ChainlinkFeedAdapter), and the reopen grace holds when

$$\text{calendar set} \;\wedge\; t_{\text{now}} > \text{maxAgeInSession} \;\wedge\; \exists\, t \in \big[\max(\text{updatedAt},\ t_{\text{now}} - \text{maxAgeInSession}),\ t_{\text{now}}\big] : \neg\,\text{isOpen}(t)$$

— that is, the market was closed at some instant since the answer was published, within the last in-session window, so the answer is a price from before the closure and the feed has not yet published in the new session (ChainlinkFeedAdapter). The interval is checked as a whole: against each holiday range, and against the weekly window's start offset (as configured and one hour earlier, for daylight saving) (ChainlinkFeedAdapter). So a closure shorter than the window, such as a one-day holiday, counts as fully as a weekend.

Three consequences of the order:

• The hard cap is checked before the calendar and is never softened. A feed that has stopped is unusable at maxAgeHard, weekend or not.
• The calendar is checked before the age. A price that is one minute old is still MarketClosed while the market is shut.
• The grace is checked before the age, too. An answer published before the last closure is MarketClosed during the grace even when it is younger than maxAgeInSession — after a one-day holiday, the pre-holiday answer is not Fresh. A round published after the reopen starts the interval after the closure, so it is Fresh immediately. The grace ends on its own: once a new round lands, or once the clock is maxAgeInSession into the session.

WETH and USDG adapters have no calendar, so for them steps 4 and 5 never apply.

What serves a price, and what needs Fresh

Two different questions, answered by two different functions.

Can a price be read? latestRoundData on the adapter reverts for OraclePaused, InvalidAnswer, HardStale and StaleInSession, and serves the last answer for Fresh and MarketClosed (ChainlinkFeedAdapter). The TokenDataStream in front of it adds its own age cap and a positivity check (TokenDataStream · 0xCa6c…3045). So over a weekend, health checks and valuations keep working on Friday's price.

Is the price Fresh? Actions that open or raise risk require priceStatus to be exactly Fresh (0) for both the collateral and the borrow token (LendingPoolRouter):

Both flags are on for every market (read 12 October 2026, again at block 92690105, on all five markets at block 94915008, on MSFT/USDG and AAPL/USDG at block 99393260, and on QQQ/USDG, GOOGL/USDG and AMD/USDG at block 113204091). A stale USDG feed therefore stops borrowing and liquidation in every market at once.

Freshness windows

Read on 12 October 2026, and unchanged at block 92690105. The SPCX and TSLA adapters, added on 22 October 2026, have the same two windows, and TokenDataStream's effective cap for both tokens is 349,200 s (block 94915008). So do the MSFT and AAPL adapters, and the QQQ, GOOGL and AMD adapters added on 13 November 2026, with the same 349,200 s cap for their tokens (block 113204091). The TokenDataStream cap is a backstop, set equal to the adapters' hard cap so the adapter decides.

Every feed has a 24-hour heartbeat, so 26 hours in session leaves two hours of slack between rounds. A weekend is longer than 26 hours, which is why the calendar matters: from Friday's close to the Sunday reopen the status is MarketClosed, not StaleInSession. After the reopen, Friday's price is older than 26 hours, so it is not Fresh; the reopen grace keeps it MarketClosed rather than StaleInSession until the first new round makes it Fresh. Borrowing and liquidation wait for that round. After a one-day holiday the pre-holiday price can still be under 26 hours old at the reopen; the grace keeps it MarketClosed all the same, and the first new round — about a minute after the reopen, as measured after Labor Day 2026 — makes it Fresh. The hard cap, 97 hours, has to outlast the longest closure, a weekend joined to a holiday (about 81 hours measured).

The calendar

Whether the market is open is computed on-chain by MarketCalendar (MarketCalendar · 0x9181…aD04).

Position in the week. Seconds since Monday 00:00 UTC:

$$o = (t + 3 \times 86{,}400) \bmod 604{,}800$$

The Unix epoch fell on a Thursday; adding three days moves the origin to Monday.

The weekly window $[s, e)$ is stored in those units and may wrap past Monday 00:00. It is closed when

$$\begin{cases} s \le o < e & s < e \\ o \ge s \;\vee\; o < e & s > e \text{ (wraps)} \end{cases}$$

Daylight saving. With autoDst on, both ends move one hour earlier while US daylight saving is in effect: from the second Sunday of March at 07:00 UTC to the first Sunday of November at 06:00 UTC, computed on-chain from the date.

$$(s, e) \leftarrow \big((s + 604{,}800 - 3{,}600) \bmod 604{,}800,\ (e + 604{,}800 - 3{,}600) \bmod 604{,}800\big)$$

Holidays are absolute ranges $[\text{start}, \text{end})$; the market is closed inside any of them.

Mainnet: $s = 435{,}600$ (Saturday 01:00 UTC), $e = 3{,}600$ (Monday 01:00 UTC) — Friday 20:00 to Sunday 20:00 Eastern Standard Time. autoDst is on and 21 holiday closures are configured (closureCount() at block 92690105).

Worked: at $t = 1792420603$ (Monday 19 October 2026, 14:36:43 UTC, block 92690105):

$$o = (1792420603 + 259200) \bmod 604800 = 52603 \;(\text{Monday } 14{:}36{:}43)$$

Daylight saving is in effect, so the window is $(432000, 0)$: Saturday 00:00 UTC to Monday 00:00 UTC, still Friday 20:00 to Sunday 20:00 Eastern. It wraps ($s > e$), and $52603 \ge 432000$ is false, $52603 < 0$ is false: open. Five days later, $o = 484603 \ge 432000$: closed. The calendar agrees: at that block weeklyCloseWindowAt returned $(432000, 0)$, and isOpen returned true for $t$ and false for $t + 432000$.

A weekend

A weekend, Friday close to Monday

In-session window

Live: 26 h in sessionIllustrative: 1 h in session

UTC offset

Daylight saving (EDT)Standard time (EST)

Scroll sideways to see Monday →

What a weekend does to a position

The price is frozen; the debt is not. Interest keeps accruing every second the market is closed, and is booked at the next accrual. Over a closed window of $\Delta t$ seconds, at an unchanged rate, a position's debt grows by

$$\Delta d \approx d \cdot \frac{r\,\Delta t}{Y}$$

and its health factor falls by the same proportion, on a price nobody can react to.

Worked, the illustrative position from position health over the 48-hour weekly window at the illustrative market's 2.3759375% APR:

$$\Delta d = 2402.294128 \times 0.023759375 \times \frac{172800}{31536000} \approx 0.3128 \text{ USDG}$$

HF moves from 1.22533 to 1.22517 — negligible at that rate. At 90% utilisation on the same launch curve (54% APR) the same weekend adds about 7.11 USDG and HF falls to 1.22171. The real weekend risk is the price gap at the reopen, not the interest; see risks.