Mechanics
pump.fun's own docs do not describe bundling. The open-source tools that do describe it say:
- The token is created and buys from many sub-wallets execute at block 0, the earliest block of the launch.
- A funder wallet sends SOL to each sub-wallet in amounts set by the configured buy sizes.
- An on-chain address lookup table lets many accounts fit into one transaction.
- Transactions go as a Jito bundle with a tip, and the bundle is atomic: all of it lands or none of it does.
- Variants stagger the later buys, or bundle only the dev buy and the first wallet.
Wallet counts differ by tool, and one repository says the limit fell to 13 wallets after a pump.fun update, which is a single developer's report.
Why it matters to buyers
One party controlling many wallets that buy at block 0 can end up holding a large share of supply. Some tools advertise avoiding detection as insiders. Check holder concentration and whether the dev wallet sells before buying. Axiom's Pulse has a Bundle % filter for this, see Axiom filters. A glossary entry is what a bundle is.
Some bundler tools come with paid licences or unvetted code, so caution applies to using them. See the bundlers category and how to launch a coin on pump.fun.