Opening buy & sniper protection

The creator’s tax-free opening buy, the 3-second surcharge, and the 25-wallet allowlist.

On this page

The opening buy

Rule: Portal 8
Rule	Portal 8
Required	Yes. A launch without one is refused.
Who pays	The wallet that sends the launch.
Recipient	Exactly one address. Anything except a protocol contract.
Minimum	0.01% of the bond value: 4.50 USDC on a USDC pair. Other assets are in Portal 8 overview.
Maximum	It may not reach the bond. If it would, the whole launch is refused.
Tax	None. No tax, no base fee, no surcharge.
Timing	Inside the launch transaction, before anyone else can trade.

The minimum exists because a pool nobody has bought into holds no quote asset, so a sell into it would fill with nothing.

The opening surcharge

For 3 seconds after launch, every trade pays a surcharge on top of the normal fee. It starts at 99% and drops each second. It applies to buys and sells, and all of it goes to the treasury.

Seconds after launch: What a trade pays
Seconds after launch	What a trade pays
0	99% of the trade in total. The surcharge is capped so tax, base fee and surcharge together are 99%.
1	The normal fee plus 6.18%.
2	The normal fee plus 0.19%.
3 and later	The normal fee only.

Seconds are block timestamps, counted from the launch block’s timestamp. Arc produced 2,000 blocks in 1,015 seconds when measured on 2026-09-22, so each second spans about two blocks.

The snipe allowlist

A launch can name up to 25 wallets that skip the surcharge. They buy with their own funds at the market price, like everyone else.

Rule: Detail
Rule	Detail
Waives	The surcharge only. Listed wallets still pay the tax and the 1% base fee.
Starts	The block after the launch block. In the launch block itself, listed wallets pay the full surcharge.
Set	Once, at launch. It can never be added to or changed.
Checked against	The address that sends the transaction.
Refused at launch	More than 25 entries, the zero address, or a duplicate.

Which wallets can be listed

Wallet: Works?
Wallet	Works?
Regular wallet that sends its own transactions	Yes.
Safe	Only by listing the owner who executes the Safe transaction. The Safe’s own address never matches.
Smart account sent through a bundler, such as Coinbase Smart Wallet	No. The bundler sends the transaction, so no listed address can match.
Relayed or gasless transaction	No. The relayer is the sender.

The opening buy

Rule: Portal 8
Rule	Portal 8
Required	Yes. A launch without one is refused.
Who pays	The wallet that sends the launch.
Recipient	Exactly one address. Anything except a protocol contract.
Minimum	0.01% of the bond value: 4.50 USDC on a USDC pair. Other assets are in Portal 8 overview.
Maximum	It may not reach the bond. If it would, the whole launch is refused.
Tax	None. No tax, no base fee, no surcharge.
Timing	Inside the launch transaction, before anyone else can trade.

The minimum exists because a pool nobody has bought into holds no quote asset, so a sell into it would fill with nothing.

The opening surcharge

For 3 seconds after launch, every trade pays a surcharge on top of the normal fee. It starts at 99% and drops each second. It applies to buys and sells, and all of it goes to the treasury.

Seconds after launch: What a trade pays
Seconds after launch	What a trade pays
0	99% of the trade in total. The surcharge is capped so tax, base fee and surcharge together are 99%.
1	The normal fee plus 6.18%.
2	The normal fee plus 0.19%.
3 and later	The normal fee only.

Seconds are block timestamps, counted from the launch block’s timestamp. Arc produced 2,000 blocks in 1,015 seconds when measured on 2026-09-22, so each second spans about two blocks.

The snipe allowlist

A launch can name up to 25 wallets that skip the surcharge. They buy with their own funds at the market price, like everyone else.

Rule: Detail
Rule	Detail
Waives	The surcharge only. Listed wallets still pay the tax and the 1% base fee.
Starts	The block after the launch block. In the launch block itself, listed wallets pay the full surcharge.
Set	Once, at launch. It can never be added to or changed.
Checked against	The address that sends the transaction.
Refused at launch	More than 25 entries, the zero address, or a duplicate.

Which wallets can be listed

Wallet: Works?
Wallet	Works?
Regular wallet that sends its own transactions	Yes.
Safe	Only by listing the owner who executes the Safe transaction. The Safe’s own address never matches.
Smart account sent through a bundler, such as Coinbase Smart Wallet	No. The bundler sends the transaction, so no listed address can match.
Relayed or gasless transaction	No. The relayer is the sender.