IPv4 addresses are finite internet infrastructure resources governed by regional internet registries, often called RIRs. With the global free pool exhausted more than a decade ago, IPv4 space now trades on a secondary market that works differently from many asset classes investors know.
For ISPs, hosting companies, cloud providers, and data centers, acquiring IPv4 space is often a practical operating need. For investors focused on technology or infrastructure, understanding how this market works is an important step before committing capital.
This article explains what drives scarcity, how transfers work across major registries, what affects valuation, and how to run a practical due-diligence process.
Key Takeaways
-
Scarcity is structural. IPv4 uses 32-bit addresses, as defined in RFC 791, which caps the total space at roughly 4.3 billion addresses. IANA's free pool was exhausted on February 3, 2011, and every major RIR has since depleted its own reserves.
-
Buyers acquire usage rights, not traditional property. RIRs such as ARIN, RIPE NCC, and APNIC administer registration and usage rights under their own policies. These rights are not property titles in the conventional sense. Legal and tax advice is important before any transaction.
-
Transfers can happen within and between registries. Both intra-RIR and inter-RIR transfers are possible when policies align. Each registry has its own verification, documentation, and approval process.
-
Valuation depends on practical factors. Block size, reputation history, geolocation data, RPKI status, and clean registry records all influence what buyers are willing to pay.
-
Due diligence is essential. Validate registrant records through RDAP, check blocklists, confirm RPKI and ROA status, and verify the seller's authority before engaging a broker or marketplace.
-
Broader digital infrastructure discussions can provide market context, but they should not replace transaction-level review.
What Makes IPv4 an Investable Digital Asset
The Internet Protocol version 4 specification defines addresses as fixed-length, four-octet values. In plain terms, that 32-bit design means the total address space can never grow beyond about 4.3 billion unique addresses.
IANA's central free pool was fully distributed to the five RIRs on February 3, 2011, according to the Number Resource Organization. After that, each RIR drew down its own reserves:
-
APNIC entered its restrictive Final /8 phase on April 15, 2011.
-
ARIN announced depletion of its free pool on September 24, 2015.
-
RIPE NCC made its final standard allocation on November 25, 2019, and now issues a single /24, or 256 addresses, per eligible Local Internet Registry through a waiting list.
These milestones shifted IPv4 acquisition from a routine administrative process to a market-driven one.
Still, IPv4 blocks should not be treated like ordinary real estate or securities. RIRs register usage rights under their own policies and agreements, such as ARIN's Registration Services Agreement. Policies and legal treatment vary by region, so professional advice is important.
IPv4 Marketplace Basics
The secondary market for IPv4 addresses generally takes three forms: direct negotiations between parties, brokered transactions through specialized marketplaces, and, less often, auction-style sales.
Buyers typically acquire blocks for network expansion, lower dependence on carrier-grade NAT, or more direct control over IP reputation for services such as email.
Because there is no single centralized exchange, price discovery can vary. Block size, registry region, and current demand all matter. Smaller blocks, such as a /24, often carry a higher per-address cost than larger aggregate blocks because they create more routing overhead and are easier for smaller buyers to absorb.
How Transfers Work Across ARIN, RIPE NCC, and APNIC
IPv4 transfers are administrative as well as commercial. The buyer and seller may agree on price and terms, but the relevant registry must still approve the transfer and update its records.
Intra-RIR vs. Inter-RIR Transfers
Most transactions happen within a single registry's jurisdiction. A seller and buyer both registered with ARIN, for example, follow ARIN's specified transfer policy.
Inter-RIR transfers, where addresses move from one registry region to another, are also possible when the counterpart RIR permits them. ARIN and RIPE NCC both support inter-RIR transfers with each other, subject to each registry's rules.
Verification and Registry Tickets
Each RIR requires both parties to submit documentation verifying identity, organizational standing, and, in some cases, demonstrated need for the addresses.
The registry opens a transfer ticket, reviews the submission, and updates its records upon approval. Timeframes vary by registry and by how complete the documentation is.
Policy References
Before entering a transaction, review the relevant registry's current transfer policy directly. ARIN, RIPE NCC, and APNIC each publish transfer guidance, including procedures for inter-RIR transfers where allowed. Policies evolve, so check current versions rather than relying on summaries.
Valuation Drivers Investors Actually Use
-
Block size. A /24, or 256 addresses, is the smallest prefix most networks will accept in BGP routing tables. Larger blocks, such as /20 or /16, offer more flexibility and may command different per-address pricing because they are easier to aggregate.
-
Reputation and blocklist history. Prior use matters. Addresses previously associated with spam or abuse may appear on blocklists such as the Spamhaus Block List, which can affect email deliverability and general usability.
-
Geolocation fit. Commercial IP geolocation databases associate addresses with locations, but accuracy is approximate. Buyers often prefer blocks geolocated near their target user base, though geolocation records can be updated after transfer.
-
RPKI and ROA status. Resource Public Key Infrastructure and Route Origin Authorizations help validate which autonomous system may announce a prefix. This reduces the risk of route hijacking, and clean routing security records are increasingly expected.
-
Registry records. RDAP, the modern replacement for legacy WHOIS, helps buyers verify current registration details. Clear records with no disputes or encumbrances are a positive signal.
-
Fragmentation. Blocks that are split into many smaller prefixes and cannot be aggregated into a single routable prefix are generally less desirable for BGP routing.
Due-Diligence Checklist
-
Validate the registrant. Query RDAP through the relevant RIR to confirm current registration and review the chain of custody.
-
Confirm the seller's authority. Make sure the Letter of Authorization matches registry records and that a valid transfer ticket can be opened.
-
Check RPKI, ROA status, and IRR entries. Look for existing Route Origin Authorizations and Internet Routing Registry objects that could conflict with your intended use.
-
Scan major blocklists. Check Spamhaus SBL, CBL, and other reputation sources. Blocklist history does not always disqualify a block, but it should affect pricing, timing, and remediation planning.
-
Review geolocation data. Check databases such as MaxMind GeoLite2 and expect some inaccuracy. Plan for geolocation correction after transfer if needed.
-
Confirm there are no active disputes. Verify through the registry that the block is not subject to pending claims, court orders, or policy disputes.
-
Plan post-transfer updates. Budget time for reverse DNS configuration, ROA creation, IRR updates, abuse-contact setup, and geofeed publication after the transfer closes.
Where to Source Addresses
Buyers generally have three paths: private-party deals, brokered marketplaces, and auctions. Each option has different tradeoffs.
Private-party deals can offer flexibility on terms, but they require the buyer to manage verification, escrow, and registry coordination independently.
Brokered marketplaces typically provide inventory verification, escrow services, and help with RIR transfer tickets. If you use a brokered marketplace, compare how providers verify inventory, manage funds, and coordinate registry steps before you buy IP addresses. Not all brokers operate the same way, so evaluate their process against your own due-diligence requirements.
Auctions can offer clearer price discovery, but they may limit negotiation on terms, timing, and post-sale support.
Costs and Ongoing Responsibilities
Beyond the acquisition cost, buyers should expect ongoing obligations. Some RIRs require membership or annual registration fees. Routing security hygiene, including ROA maintenance and IRR updates, is an ongoing task.
Reputation monitoring through blocklist checks and responsive abuse handling helps protect the long-term usability of the block. Administrative upkeep, including current registry contact information, is simple but important.
Risks and Mitigations
-
Fraud and hijacking. Verify every transaction through the relevant RIR's transfer process. RPKI adoption reduces the risk of unauthorized route announcements.
-
Reputation baggage. Inherited blocklist entries can often be remediated, but the process takes time. A conservative traffic ramp-up after acquisition can help establish a cleaner usage history.
-
Transfer denials. Registries can deny transfers that do not meet policy requirements. Complete documentation and alignment with current RIR policy reduce this risk.
-
Regional policy mismatches. Inter-RIR transfers require compliance with both the sending and receiving registry's rules. Confirm compatibility before committing to a cross-region deal.
Outlook: IPv6 and the Medium-Term Case for IPv4
IPv6 adoption continues to grow, and it should reduce reliance on IPv4 for many use cases over time. For now, many customer-facing internet services still depend on IPv4 reachability, and dual-stack networks keep demand steady.
Secondary-market pricing can shift with supply, demand, registry policy, and operating needs. Buyers should treat IPv4 blocks as practical infrastructure resources rather than speculative assets with a guaranteed price path.
FAQ
Is buying IPv4 addresses legal in the United States?
IPv4 transfers are policy-governed processes administered by RIRs such as ARIN. They are not generally prohibited by law, but the legal and tax treatment can be nuanced. Consult a qualified attorney and tax advisor before proceeding.
How long does a transfer typically take?
Timeframes vary by registry, transaction complexity, and documentation quality. There is no standard duration. A transfer may take a few weeks or several months.
Can I lease IPv4 addresses instead of buying them?
Leasing arrangements exist, but the terms, risks, and RIR policy implications differ from outright transfers. Review the relevant registry's policies and contract obligations carefully.
What is the smallest block I can practically use?
A /24, or 256 addresses, is widely regarded as the smallest prefix accepted in global BGP routing tables. Smaller allocations may not be routable across the broader internet.
What is the difference between WHOIS and RDAP?
WHOIS is the legacy protocol for querying internet registration data. RDAP, or Registration Data Access Protocol, is its standardized replacement. RDAP provides more consistent output and is the preferred tool for due diligence across ARIN and other registries.
