OKX to execute a rebase on ANTHROPIC perpetuals and X-Perp

Published on Nov 11, 20267 min read

Dear OKX customers,

OKX will execute a rebase on the ANTHROPIC-USDT-SWAP and ANTHROPIC-USD_UM_XPERP-310912 contracts at 17:00 on November 12, 2026 (UTC+8), adjusting their pricing basis from the original estimated share count to an IPO reference share count calculated from Anthropic’s offering disclosures. The adjustment ratio applied to this rebase will be 1.3116.

1. What is a rebase?

A rebase is a one-time proportional adjustment to contract quantities and prices. Pre-IPO contracts use a per-share pricing basis:Contract price × Total shares outstanding ≈ Company valuationBefore relevant share-count information is publicly disclosed, contracts are priced using an estimated share count. A rebase adjusts this pricing basis following disclosure. The IPO reference share count used for this event is an adjusted estimate based on the offering documents and the assumptions below, rather than a finalized post-offering share count.A rebase is designed to be value-neutral: position quantities are multiplied by the adjustment ratio, while prices are divided by it. Excluding market movements, funding fees and rounding differences, the rebase itself does not change position value or account equity.For details, refer to Pre-IPO perpetual futures and Corporate actions handling mechanism.

2. Affected contracts and schedule

Item	`ANTHROPIC-USDT-SWAP`	`ANTHROPIC-USD_UM_XPERP-310912`
Instrument ID (instId)	`ANTHROPIC-USDT-SWAP`	`ANTHROPIC-USD_UM_XPERP-310912`
Rebase start time	November 12, 2026, 17:00 (UTC+8)	November 12, 2026, 17:00 (UTC+8)
Estimated share count	10,000,000,000 shares	10,000,000,000 shares
IPO reference share count (adjusted estimate)	13,116,075,288 shares	13,116,075,288 shares
Applied adjustment ratio	1.3116	1.3116
Contract face value	1	1
Tick size after rebase	Unchanged	Unchanged
Lot size	Unchanged	Unchanged
Minimum order size	Unchanged	Unchanged

The Anthropic IPO reference share count used for this event is 13,116,075,288 shares, calculated as follows:

Component	Shares
Disclosed post-offering shares	13,086,672,593
Add: subsequent acquisition shares excluded from the base (1)	561,963
Add: subsequent acquisition shares excluded from the base (2)	848,882
Add: subsequent donation-matching shares issued	27,991,850
Total IPO reference share count	13,116,075,288

Amazon conversion is included: the count already includes 276,827,518 shares from Amazon’s conversion, with no further addition for those shares. Potential shares underlying the remaining unconverted notes are excluded.
Locked-up shares are included: secondary sales of existing shares are not double-counted. Unexercised options, unsettled RSUs and unissued reserves are excluded. This is therefore not a fully diluted share count.
Estimate status: this is an adjusted estimate and remains subject to updates from the final offering documents.

Dividing the reference share count by the original estimated share count gives 13,116,075,288 ÷ 10,000,000,000 = 1.3116075288. The rebase ratio actually applied for this event is 1.3116.Source: November 10, 2026 S-1/A filing.

Trading resumption

The trading suspension will depend on processing and verification progress. Once adjustments are complete, the affected contracts will enter a Post-only phase lasting at least 10 minutes. OKX will resume normal trading based on order book and market conditions. Please refer to each contract’s actual trading status and the latest notices.

3. Adjustments to positions and orders

Item	Adjustment
Position quantity	Original quantity × 1.3116, for both long and short positions
Mark price reference	Pre-rebase mark price ÷ 1.3116; normal calculation subsequently resumes under the applicable rules
Unrealized PnL	Existing positions are settled at the pre-rebase mark price. Unrealized PnL becomes realized PnL and is reflected in the account balance
Entry price of the new position	Positions are reopened at the adjusted mark price, rather than at the original entry price divided by 1.3116
Fully unfilled limit orders	Eligible orders have their price divided by 1.3116 and quantity multiplied by 1.3116, retaining their original order IDs
Partially filled limit orders	Only the remaining unfilled portion is adjusted: price ÷ 1.3116 and quantity × 1.3116. Reposted orders receive new order IDs. Existing execution records remain unchanged, and positions arising from filled portions follow the position adjustment rules
Untriggered TP/SL orders	Position TP/SL, order TP/SL and trailing stop orders are canceled and will not be restored automatically
Trading strategies	Running trading bots are stopped; trigger orders and chase orders are canceled. Please recreate them as needed after trading resumes
Fees for system settlement and reopening	No trading fees are charged for closing and reopening positions as part of the rebase. Normal funding fees and fees for customer-initiated trades remain subject to the applicable rules

Precision handling:

Absolute position quantities and unfilled order quantities are rounded down to each contract’s existing lot size.
Buy order prices are rounded down and sell order prices are rounded up to the 0.01 tick size.
Orders are canceled if the rounded quantity is zero, falls below the minimum order size, or fails other trading validations.
Position rounding differences are handled under the applicable settlement rules. Please reconcile realized PnL, rounding records and balance changes together.

4. Impact on trading services

During rebase processing

Order placement, amendment, cancellation and matching are suspended for the affected contracts. Please complete any intended position or order adjustments before the suspension begins.

During the Post-only phase

Only Post-only orders may be submitted. Existing Post-only orders may be amended or canceled. Market, IOC, FOK and regular limit orders, as well as new TP/SL and trigger orders, are unavailable.Entering the Post-only phase does not mean normal order matching has resumed. Normal trading does not automatically resume when 10 minutes have elapsed.

After normal trading resumes

Please check position quantities, entry prices, realized PnL, account balances and open orders. Reconfigure TP/SL orders and relevant strategies using the adjusted prices and position quantities.

5. Illustrative example

Using ANTHROPIC-USDT-SWAP as an example, assume a customer holds a long position of 10,000 contracts with a contract face value of 1, an entry price of 100 USDT and a mark price of 131.16 USDT at the time of the rebase. Applying the 1.3116 adjustment ratio:

Item	Before rebase	Immediately after rebase settlement
Position quantity	10,000 contracts	13,116 contracts
Mark price	131.16 USDT	100 USDT
Entry price	100 USDT	100 USDT
Unrealized PnL	311,600 USDT	0
Realized PnL from this settlement	—	+311,600 USDT
Position notional value	1,311,600 USDT	1,311,600 USDT

The original unrealized PnL has become realized PnL; it has not been lost. The new entry price is the pre-rebase mark price divided by the adjustment ratio: 131.16 ÷ 1.3116 = 100 USDT.This example illustrates the calculation only and excludes market movements, funding fees and rounding differences. Actual quantities must satisfy the contract’s lot size requirements.

6. Notice for API users

This rebase applies to the ANTHROPIC-USDT-SWAP and ANTHROPIC-USD_UM_XPERP-31310912 contracts.After the rebase, the instrument IDs (instId) visible to and used by API users will remain unchanged:

ANTHROPIC-USDT-SWAP
ANTHROPIC-USD_UM_XPERP-310912

After the rebase, UI display names will map to API instrument IDs as follows:

UI display name	API instrument ID (instId, unchanged)
ANTUSDT	`ANTHROPIC-USDT-SWAP`
ANTUSD UM	`ANTHROPIC-USD_UM_XPERP-310912`

UI display names do not replace the API instrument IDs. API users should continue using the original instrument IDs above for queries, subscriptions and trading, and should not use ANTUSDT or ANTUSD UM as an instId.After trading resumes, please synchronize positions, open orders, balances and trading parameters. Fully unfilled orders retain their original order IDs, but their prices and quantities are adjusted. Reposted unfilled portions of partially filled orders receive new order IDs, which should be reflected in your local order records.

7. Risk notice

A rebase does not generate additional returns or confer ownership of Anthropic shares or securities. Contract prices do not represent Anthropic’s official valuation, final IPO offering price or post-listing share price.Please manage your positions and margin appropriately before the rebase. Market volatility may occur before and after the adjustment, and normal risk management rules continue to apply after trading resumes. Canceled TP/SL orders will not be restored automatically. Please reconfigure them promptly once normal trading resumes.

Thank you for your understanding and support.

OKX Team

Nov 11, 2026

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