Kilobar
A kilobar is a 1,000-gram gold bar — approximately 32.15 troy ounces — produced to investment fineness and used as the working unit of settlement across the physical gold market outside central-bank-scale reserves. Its weight sits at the point where a single bar is large enough for institutional allocation yet small enough to move, divide, and re-vault without recasting, which is why it dominates cross-border settlement, refinery output, and allocated holdings. The format also carries a defined role in exchange delivery and customs classification that separates it from both the 400-ounce London bar and smaller minted bars.
Definition and Market Position
A kilobar holds one kilogram of refined gold, typically at 999.9 fineness. It occupies the middle of the bar hierarchy: above the gram and ounce minted bars held by private investors, and below the roughly 400-ounce Good Delivery bar that sits in central-bank vaults and physically backed exchange-traded funds.
The two reference markets use different bars, and the kilobar is what makes the gap bridgeable. London Good Delivery is built on the ~400-ounce bar at a minimum fineness of 995; COMEX in New York settles in kilobars and 100-ounce bars at investment fineness. A 400-ounce London bar is not COMEX-deliverable as cast — it has to be refined and re-poured into kilobars first. The kilobar has since been admitted to the LBMA Good Delivery framework as an accepted 999.9 standard, formalizing a unit the wider market had already adopted as its default.
Kilobars are cast and minted by LBMA-accredited refiners. Argor-Heraeus SA and Heraeus Precious Metals are among the producers whose 1 kg formats circulate in institutional supply, alongside the broader set of refiners on the LBMA Good Delivery List.
Physical Specifications
| Parameter | Specification |
|---|---|
| Weight | 1,000 grams (32.15 troy ounces) |
| Purity | Typically 999.9 (COMEX contract floor: 995) |
| Dimensions (approx., cast) | Length 117 mm · Width 53 mm · Height 8–9 mm |
| Form | Cast or minted |
| Markings | Refiner’s hallmark, serial number, fineness, and weight — and, for COMEX-deliverable gold produced from 1 January 2026, the month and year of production |
Cast and minted kilobars serve different ends. Cast bars are the workhorse of institutional storage and exchange delivery; minted bars, with finished surfaces and precise edges, circulate more in private holdings and dealer distribution.
Manufacturing and the 400 oz to 1 kg Recasting Flow
Kilobars are produced by LBMA-accredited or ISO 9001-certified refineries from doré, recycled metal, or larger bars. The standard sequence runs from refining the feedstock to investment fineness, through casting or minting into 1 kg form, stamping of serial numbers and purity marks, assay certification, and registration for vault delivery or export.
A distinct and high-volume source of kilobar production is the conversion of 400-ounce Good Delivery bars. Recasting a 995-fine, ~400-ounce bar into a series of 999.9 kilobars is not a simple remelt: it involves a chemical refining step to raise fineness, which is why refiners treat Good Delivery conversion as a separate input stream alongside mine doré and scrap. This conversion is what physically links the London market to New York — bars crossing the Atlantic are routed through Swiss refineries to be re-poured into the kilobar format COMEX requires.
The dependence on that route became visible in early 2025, when demand to move gold into US warehouses surged. More than 61 billion dollars of bullion flowed into the United States, the withdrawal queue at the Bank of England stretched beyond four weeks, and Swiss refineries ran continuously to keep pace, with gold lease rates holding at roughly three times their normal level. The episode showed that the kilobar’s settlement role rests on finite refining and logistics capacity, not on an abstract market convention.
COMEX Delivery Standard
The COMEX gold contract is 100 troy ounces, deliverable as either one 100-ounce bar or three kilobars, against a minimum fineness of 995 and a weight tolerance of five percent. Because the 100-ounce bar sees little use internationally, the kilobar is the practical COMEX-deliverable unit at scale, and a short position seeking physical settlement is in effect obtaining kilobars.
For metal produced on or after 1 January 2025, COMEX delivery rules require the month and year of production to be incised on deliverable precious-metal bars, to improve transparency over production date. For gold specifically — both 100-ounce and kilo bars — that effective date was deferred to metal produced on or after 1 January 2026; the 2025 date continues to apply to silver, platinum, and palladium. The production date may be carried within the serial number or marked separately in MMYYYY or MMYY form.
Customs Classification and the 2025 Tariff Episode
The customs code a kilobar travels under can change its cost of delivery, as a 2025 episode demonstrated. On 8 August 2025, a US Customs and Border Protection ruling letter dated 31 July classified 1 kg and 100-ounce cast gold bars under Harmonized System code 7108.13.5500 — treated as semi-manufactured — rather than the 7108.12.10 line the trade had assumed was exempt. That classification exposed the bars to country-specific reciprocal tariffs of up to 39 percent on Swiss-origin metal.
Because kilobars make up the bulk of Switzerland’s gold exports to the United States — exports valued at about 61.5 billion dollars in 2024 — the ruling disrupted the COMEX supply chain immediately. The December contract premium over London spot widened past 100 dollars an ounce, and several Swiss and Asian refiners paused US shipments. The matter was resolved on 5 September 2025, when Executive Order 14346 set a zero tariff rate for gold bars from aligned-partner countries under a defined set of HS codes — including 7108.11.00, 7108.12.50, 7108.13.10, 7108.13.55, 7108.13.70, and 7108.20.00 — for entries made after 8 September 2025. The sequence underlines that physical kilobar settlement is sensitive not only to fineness and weight standards but to tariff and classification policy.
Settlement in Asian and Middle Eastern Markets
Outside the COMEX and London systems, the kilobar is the standard physical unit across the principal Asian and Middle Eastern markets. It is the benchmark delivery size on the Shanghai Gold Exchange and the Dubai Multi Commodities Centre, supporting settlement between refiners, dealers, and financial institutions. In these markets kilobars are quoted in grams or kilograms rather than troy ounces, which aligns with metric conventions and simplifies customs documentation for import and export.
Storage, Audit, and Compliance
In allocated storage, each kilobar is individually numbered and listed in client barlists for insurance and audit purposes. The manageable weight makes the format suitable for diversification across regional vaults, for partial allocation where dividing a 400-ounce bar would be impractical, and for physical redemption from gold-backed products.
Kilobars entering professional supply are expected to conform to the LBMA Responsible Gold Guidance, OECD due-diligence guidance for supply-chain integrity, and FATF anti-money-laundering and know-your-customer standards. Independent audits confirm that each bar’s serial number and certificate correspond to the physical holding, and bars in institutional storage are included in periodic vault audits and insurance reconciliations to maintain traceability.
Institutional and Private Relevance
The kilobar functions as the common denominator of physical gold ownership. For institutions it provides divisibility and ease of transfer between vaults and jurisdictions; for private holders it is a globally recognized, fungible unit that can be stored, insured, or redeemed without conversion. Within the custody chain it is the operational bridge between large-scale reserve bars and individual holdings, carrying the same standards of fineness, auditability, and documentation that define the professional gold market.
Golden Ark Reserve coordinates the purchase, allocated storage, and delivery of 1 kg gold bars for qualified counterparties.
Sources
- COMEX delivery standard and bar-marking requirements (100 oz contract, three-kilobar delivery, production-date marking): CME Group, COMEX Rulebook, Chapter 126 — Gold (Enhanced Delivery) Futures
- London-to-New York recasting flow and the early-2025 demand surge: SWI swissinfo.ch
- 2025 customs classification and the gold-bar tariff exemption (Executive Order 14346, with the aligned-partner HS codes): Federal Register