Prime Broker — Definition and Single Source of Truth
A prime broker centralises trade execution, custody, financing, and reporting for a hedge fund. The result: one canonical record of positions and cash.
- A prime broker is a single counterparty that provides custody, trade execution clearing, financing, and reporting to a hedge fund.
- Because all trades clear and all assets sit at the prime, the prime's books are the canonical source of positions and cash.
- Multi-venue retail traders have no equivalent single source of truth, which is exactly why NakedPnL aggregates and chains data from each venue independently.
Definition
Prime brokerage is a bundle of services offered by a major bank or broker-dealer to professional trading entities, primarily hedge funds. A prime broker provides custody of the fund's securities and cash, clears and settles trades that the fund executes (with the prime or with executing brokers under a give-up arrangement), provides margin financing and securities-lending services, and produces a daily statement that reflects every position, every cash movement, and every unrealised P&L number. Major US providers include Goldman Sachs, Morgan Stanley, JP Morgan, and BNY Pershing.
Why a prime broker is a single source of truth
When a fund uses one prime broker, every trade ultimately clears at that prime, every asset is held in custody there, and every cash movement runs through accounts at that prime. The fund's external administrator strikes NAV against the prime's daily statement; the auditor reconciles year-end financials against the prime's statement; the LPs receive investor reports that ultimately trace back to the prime's statement. Disputes about positions or cash are resolved against the prime's books because there is no second venue holding economic interest in the same trade.
How that contrasts with multi-venue retail trading
A retail or proprietary trader who trades crypto on Binance, perpetuals on Bybit, options on OKX, equities on IBKR, and event contracts on Kalshi or Polymarket has no single source of truth. Each venue holds its own assets, settles its own trades, and produces its own statement. There is no top-level reconciliation across venues, no fund-administrator NAV, and no annual audit binding the figures together. The data exists, but it is fragmented across six different systems with six different schemas and six different reliability profiles.
How NakedPnL handles the multi-venue case
NakedPnL connects to each venue independently via read-only API keys (or wallet signatures for Polymarket and on-chain venues). The adapter for each venue (`lib/adapters/binance.ts`, `lib/adapters/bybit.ts`, `lib/adapters/okx.ts`, `lib/adapters/ibkr.ts`, plus the prediction-market clients) fetches the venue's daily NAV statement at 23:55 UTC. Each statement is canonicalised, hashed into a contentHash, and chained per account. Daily Merkle roots across every chain head are anchored to Bitcoin via OpenTimestamps. The result is not a single source of truth in the prime-brokered sense — it is a programmatically verified aggregation across many sources, with the cryptographic record taking the place of the single statement that prime brokerage would otherwise provide.
Worked comparison
| Dimension | Prime-brokered fund | Multi-venue retail trader on NakedPnL |
|---|---|---|
| Number of canonical sources | One prime broker | One per connected venue (up to six) |
| NAV strike | Daily by external fund administrator | Daily at 23:55 UTC by NakedPnL cron |
| Reconciliation | Administrator versus prime | Per-venue read-only fetch, content-hashed and chained |
| Audit | Annual external audit of fund financials | Continuous re-verification via /verify/chain/[handle] |
| Time anchor | Audit firm's signed report | Bitcoin-anchored Merkle root via OpenTimestamps |
When prime brokerage is required
Most institutional allocators expect a fund to use a prime broker as a baseline operational standard. AUM thresholds, leverage requirements, and the need for cross-margining usually mean the fund must consolidate at a prime above a few tens of millions in assets. Smaller funds may use a single full-service broker or a self-custody arrangement; this is one of several factors that affect institutional accessibility and is independent of any performance-publication arrangement with NakedPnL.
Related terms
- Fund administrator — the independent service provider that strikes NAV against the prime's statement.
- Net asset value — the daily figure both the prime and the administrator produce.
- Hash chain — the verification primitive NakedPnL uses to compensate for the absence of a single prime.
- Custody — one of the bundled services that defines prime brokerage.