100 oz Gold Bar
The 100 oz gold bar is a standard bullion format used across professional storage systems and investment-grade custody.
It provides a balance between the high efficiency of institutional settlement bars and the flexibility required by private investors, family offices, and smaller institutional accounts.
Definition and Market Role
A 100 oz gold bar represents precisely 100 troy ounces (approximately 3.11 kilograms) of refined gold.
It is produced by LBMA-accredited refineries and meets internationally recognized standards for purity, identification, and audit traceability.
While the 400 oz Good Delivery bar dominates interbank and central bank storage, the 100 oz bar functions as a secondary institutional and high-net-worth storage unit — large enough for efficient vaulting but small enough for fractional allocation.
These bars are widely used by private vault operators, ETF issuers, and asset managers who require physical holdings that remain tradable, movable, and easily auditable.
Physical Specifications
| Parameter | Specification |
|---|---|
| Nominal Weight | 100 troy ounces (approx. 3.11 kg) |
| Minimum Fineness | 999.9 parts per thousand (99.99%) |
| Dimensions (approx.) | Length: 60–80 mm · Width: 35–45 mm · Height: 15–20 mm |
| Form | Cast or minted bar |
| Markings | Serial number, refiner’s hallmark, fineness, and weight |
Each bar carries a unique serial number and refiner stamp, which are recorded in the vault’s barlist and insured inventory ledger.
Manufacturing and Refining
100 oz gold bars are produced under LBMA Good Delivery accreditation or equivalent ISO-certified standards.
Refining and casting include the following steps:
- Purification of gold feedstock to 99.99% fineness through electrolysis or chemical refining;
- Melting and casting into 100 oz molds with precise mass calibration;
- Cooling and finishing, ensuring surface uniformity and proper marking area;
- Stamping and registration, assigning serial numbers and hallmark identifiers;
- Assay certification, confirming purity and weight before vault acceptance.
High-purity 100 oz bars are often chosen by institutional clients requiring predictable assay values for lending, collateral, or fund-backed custody.
Storage and Custody Context
In professional vaults, 100 oz bars are stored under allocated or segregated storage models.
Each unit is identified individually and linked to the owner’s custody record, providing direct legal ownership and audit traceability.
They are covered by all-risk insurance, reconciled in quarterly vault audits, and eligible for vault-to-vault transfers under LBMA or regional standards.
Due to their smaller size compared to 400 oz bars, they are more frequently used for:
- Private and family office storage;
- Institutional sub-accounts in pooled funds;
- ETF redemption units;
- Regional vault diversification across Dubai, Singapore, or Zurich.
Liquidity and Market Access
100 oz bars are traded in both over-the-counter (OTC) and exchange environments.
They are commonly used for delivery against futures contracts on COMEX in New York, where the 100 oz specification defines the standard settlement unit for gold futures.
This dual role — as both a professional storage asset and a deliverable futures unit — gives the 100 oz bar exceptional liquidity across global trading and custody systems.
Compliance and Assurance
As with all professional bullion, 100 oz bars are subject to LBMA Responsible Gold Guidance, OECD Due Diligence, and FATF AML/KYC compliance at both refinery and vault levels.
Each bar’s serial number and assay certificate ensure verifiable provenance and authenticity.
Audit reports from independent inspection firms confirm the accuracy of holdings and the absence of unallocated exposure.
Institutional and Investment Relevance
The 100 oz gold bar bridges the institutional and private custody segments of the bullion market.
It offers a scalable format for wealth preservation, collateralization, and fund backing — large enough for efficiency yet divisible enough for flexibility.
Within professional vaulting systems, it serves as a transactable, audited, and fully insured gold unit, linking private investment to the same infrastructure that underpins global institutional custody.