Backpack SOL

Summary

Ketju does not approve Backpack SOL (bpSOL): Ketju has approved no Solana liquid-staking provider. We found no defect in bpSOL, but its pool delegates all its stake to one validator. The bpSOL token stands for SOL staked through an SPL stake pool on the Sanctum program. On 2026-10-16 the DefiLlama yield feed showed one pool with about $6.6 million at 4.95%. We read the pool account on Solana that day. It held about 62,365 SOL, all delegated to one validator.

Review triggers
• The pool delegates to many validators
• Ketju approves a Solana liquid-staking provider, which starts a new comparison that includes bpSOL

Ketju checks this memo every night and opens a review if its venues or files show a warning or a cited document changes. The first confirmation is due 2027-01-16.

Research

How it works

A holder deposits SOL into the pool and receives bpSOL. The pool delegates the SOL to validators. Staking rewards raise the amount of SOL each bpSOL redeems for, so the token does not rebase. On 2026-10-16 the pool account (ETVc1GBAiKzv2gNaA3Hfq4hsS1Mzh1NwQSxRFst7k8vz) showed about 62,365 SOL against about 55,500 bpSOL. Its validator list had one entry, vote account bkpkQKgJMQXqwZL5dRX9LMwnsz9zkZZqCtqWfnBcwDx, which held all of the active stake. The account sets a 2.5% fee on each epoch’s rewards. The yield feed labels the pool “3% epoch fee,” and we did not reconcile the two figures.

Who controls it

The same two accounts manage this pool and the BulkSOL pool: 8JS6XsMPo2u3EyeeY3p2jvzHEhdUtCKgarHpJ3PAonyv (manager) and 57V86ZRddiL4LCmVobuLybnGaxpFj41K8ZgeGwoUpyBa (staker). The manager can change fees, and the staker moves stake between validators. We did not identify who holds those keys. The stake pool program is a public Solana program with published docs.

Losses and incidents

We found no audit or bug bounty for the pool, and DefiLlama lists none. DefiLlama lists no incident. Because all stake sits with one validator, a fault, a slashing rule change or a commission change at that operator affects every holder at once.

Withdrawals

A holder can sell bpSOL on a market or redeem it through the pool for a stake account. The stake account must deactivate before it turns back into SOL, which takes until the epoch ends. At $6.6 million the pool is small beside the leading Solana liquid staking tokens. We did not measure market depth, so we do not know whether a large position can be sold at the market price.

Comparison

Marinade’s FAQ says Marinade spreads delegation among the top-performing validators through its stake auction, while bpSOL uses one validator. Ketju does not approve Marinade either: its stake now sits with 46 validators. Ketju will consider bpSOL again if the pool moves its stake to many validators, or when Ketju approves a Solana liquid-staking provider.

Provider choice

Ketju found no defect that rules this provider out. Ketju has approved no Solana liquid staking provider, so it approves none of them, this one included. Approving this provider would take its own review against the approved structures. The advisor decides what fits each client’s purpose and constraints, and records any choice and amount.

Sources

Each claim above comes from one of these sources. Where Ketju could not verify a number, the memo states that.

• Sanctum LST list, Backpack Staked SOL entry · primary · accessed 2026-10-16
  Supports: bpSOL mint, SanctumSpl pool, pool address, validator list address
• Solana mainnet RPC, stake pool and validator list accounts · primary · accessed 2026-10-16
  Supports: getAccountInfo pool and validator list, SOL held, one validator, 2.5% epoch fee, manager and staker accounts
• Solana stake pool program documentation · primary · accessed 2026-10-16
  Supports: stake pool design, fees, operation
• Backpack · primary · accessed 2026-10-16
  Supports: operator site, no audit found for bpSOL
• Marinade docs, FAQ · primary · accessed 2026-10-16
  Supports: auction-based validator spread, comparison point
• DefiLlama, Backpack SOL protocol page · secondary · accessed 2026-10-16
  Supports: no audits recorded, Liquid Staking category
• DefiLlama, yield pools feed · secondary · accessed 2026-10-16
  Supports: BPSOL pool TVL, 4.95% base rate, 3% epoch fee label

The asset and the chain

This memo covers the protocol. A position also holds an asset and settles on a chain. Whichever of the three holds the most power over the position decides who can freeze it. These tables describe control and do not judge quality.