The Open Cap Table Protocol (OCP)
A blockchain-based standard for programmable, compliant, and composable equity management, supporting the Open Cap Table Format (OCF).
The Open Cap Table Protocol (OCP) introduces a blockchain-based framework for recording and managing equity ownership in a programmable, interoperable, and composable manner. As equity ownership remains fragmented across isolated files and databases, requiring slow, costly, and manual processes to update and reconcile records, the Open Cap Table Protocol (OCP) aims to address this issue.
The Open Cap Table Protocol (OCP) is an event-driven, onchain cap table system that enables real-time ownership tracking, automated compliance, and seamless integration with financial applications.
Built as the onchain protocol of the Open Captable Format (OCF) standard, OCP ensures legal and industry compatibility while allowing equity to function as a composable financial primitive. Through modular smart contracts and a hybrid onchain/offchain architecture, OCP scales across equity securities such as stocks, convertibles, warrants, and equity compensation while preserving privacy via Role-Based Access Control (RBAC).
OCP modernizes ownership structures and creates the technical foundation for digital and disintermediated equity markets by replacing intermediaries with code and enabling previously impossible applications (DeFi), from collateralizing private equity for loans to enforcing vesting schedules or settling transactions across different blockchains.
Authors & Contributors
Thibauld Favre (Fairmint), Joris Delanoue (Fairmint), Victor Mimo (Fairmint), Adam Momen (Fairmint), Alex Fong (Plural)
The evolution of securities settlement is a story of both ingenuity and compromise. In the early days, when stock ownership was represented by physical certificates, the industry was mired in labor-intensive processes. The “paperwork crisis” of the 1960s—when the New York Stock Exchange even had to close on Wednesdays during a substantial amount of 1968 to reconcile certificate volumes—underscored the urgent need for reform [1]. Research like the Rockwell Study of 1969 proposed visionary solutions, including a “national clearing system together with a decentralized network of individual transfer agent depositories,” where each transfer agent would maintain the certificates for its issuers [2]. However, due largely to technological limitations of the era—when mainframes and databases were just emerging—the industry ultimately adopted a centralized model. Certificates were immobilized within a single entity, the National Clearing Corporation [1] (the precursor to today’s Depository Trust & Clearing Corporation [3]), which was interconnected with banks and regional clearinghouses and was responsible for maintaining a comprehensive ledger of all ownership records.
While this centralized framework has proven good enough for public markets, it also spawned a complex infrastructure of intermediaries that is effectively reserved for the world’s most successful companies. Only those with significant resources can access streamlined, regulated channels for equity movement in this system. In contrast, many companies today remain private for longer periods but lack an efficient infrastructure for transferring equity. As a result, ownership records are scattered across disparate systems—from spreadsheets to isolated private databases—and moving equity involves labor-intensive, slow, and costly legal processes that limit investors’ ability to interact with and leverage their holdings fully.
The timing for modernization has never been more opportune. In February 2025, as part of a comprehensive new regulatory framework, SEC Commissioner Pierce outlined the SEC's Crypto Task Force agenda, which includes plans to work on "the intersection of crypto and clearing agency and transfer agent rules." The Commission has specifically indicated their commitment to engage with "market participants interested in tokenizing securities or otherwise using blockchain technology to modernize traditional financial markets" [4]. This regulatory evolution signals growing recognition of the need to modernize traditional financial infrastructure.
56 years ago, a vision of a distributed network of transfer agents was hypothesized. Today, the Open Cap Table Protocol (OCP) stands as an onchain, permissioned record of cap tables that is immutable, transparent, and natively programmable. By establishing a distributed network of transfer agents and issuers—each maintaining its own records while seamlessly interoperating with others—we can eliminate the friction imposed by legacy intermediaries. This network functions as a decentralized DTCC, offering a single, scalable source of truth that empowers investors to interact with their holdings in real time.
OCP unlocks a new design space for equity securities by delivering unparalleled transparency, programmability, and composability. Investors gain direct, real-time access to a single, immutable source of truth—allowing them to verify ownership, trace historical events, and confidently audit every transaction. At the same time, equity becomes programmable: compliance rules, such as transfer restrictions, vesting schedules, and shareholder voting requirements, can be enforced automatically, and transfers can be executed seamlessly when predetermined conditions are met. Moreover, OCP enables the integration of equity data into broader financial ecosystems. For example, investors can leverage their holdings as collateral to access debt financing, unlock equity-linked financing opportunities, and incorporate their equity into complex financial contracts through smart contract interactions. In short, OCP transforms cap tables into smart contracts, turning static securities into dynamic and actionable financial instruments, paving the way for financing models that were previously too complex and expensive to execute.
OCP is open source under the MIT license, with all code available in the official Open Captable Protocol repository and upcoming (read "less stable") versions available at Fairmint's repository.
OCP is designed to become the ‘de facto’ standard for recording equity onchain. OCP is chain agnostic and supports all EVM-compatible chains, maintaining the same standardized interfaces and security guarantees across all platforms. This ensures companies can deploy their cap tables on the blockchain that best suits their needs.
OCP relies on a hybrid architecture combining onchain immutability with offchain scalability. The design consists of two synchronized components: 1. smart contracts deployed on EVM-compatible chains that maintain the authoritative record of all states and transitions, and 2. a server exposing REST APIs for efficient data access and integration. While the hybrid architecture provides additional benefits, the smart contracts can be deployed independently.
Synchronization between these two components is maintained through continuous event monitoring. When a state change occurs onchain, it is immediately reflected in the offchain database, for regulatory and compliance reasons, creating a system that leverages both blockchain's immutability and traditional databases' query performance.
OCP’s core data model is grounded in the work of the Open Cap Table Coalition, ensuring broad compatibility with existing industry standards.
Hence, the foundational structure of any cap table is defined by four primary objects:
● Issuer: Represents the root entity controlling global share authorization and tracking total shares issued. This centralized control ensures that all share issuances, regardless of class or type, operate within authorized limits.
● Stock Classes: Defines the characteristics and behavior of different equity types. Each class maintains its own share authorization limits, price per share, and issuance tracking, while operating within the Issuer's global constraints. This hierarchical structure enables precise control over dilution and share allocation.
● Stock Plans: Facilitates equity compensation programs by reserving shares from specific stock classes. These plans define vesting parameters and manage share pools, providing a structured approach to employee equity distribution while maintaining compliance with company policies and regulatory requirements.
● Stakeholders: Represents individuals and/or entities that can hold securities, implementing a secure mapping between onchain addresses and legal identities. This mapping, managed through a robust verification system, ensures that all transactions can be adequately attributed while maintaining privacy and regulatory compliance.
The runtime state of the system is maintained through two key components:
● Active Positions: Represents stock positions, convertible positions, equity compensation positions, and warrant positions.. Stock positions track quantities and prices per class, while convertible positions record investment amounts and terms. Equity compensation positions manage grants and vesting status, and warrant positions track exercise terms. A real-time tracking of security ownership has been implemented through these specialized position types, depending on the category of security. Such a tracking enables complex operations like position consolidation and transfers while maintaining a complete audit trail..
● Transactions: Refers to every state change recorded through an immutable event system. The transaction log captures basic transfer operations, as well as complex events like plan adjustments, share authorization changes, and security conversions. This creates a verifiable history that can be used for audit, state reconstruction and waterfall simulations.
Four distinct security types form the basis of the protocol, each with its behavior and constraints.
● Stock: Represents the fundamental unit of company ownership. The stock positions are tracked with precise share quantities and prices, supporting multiple stock classes with specific rights and restrictions. OCP enforces authorization limits at both the issuer and class level, preventing unauthorized dilution while enabling controlled share issuance.
● Convertible security: Refers to any convertible instrument and consists in a) tracking investment amounts rather than share quantities, b) implementing specific conversion terms and c) maintaining seniority relationships. When a complex event occurs, such as a conversion event, OCP automatically creates new stock positions while maintaining the complete transaction history.
● Equity-based compensation: Refers to options (ISO, NSO), restricted stock units (RSUs), phantom shares, restricted stock awards (RSAs) and are tightly integrated with stock plans. The system tracks exercise prices, vesting schedules, and other grant-specific terms. When exercises occur, the protocol automatically validates conditions and creates the resulting stock positions.
● Warrant: Benefits from their own specialized tracking, managing exercise conditions and purchase prices. The system maintains the relationship between warrants and their underlying stock classes, enabling controlled exercise operations when conditions are met.
While these four security types cover most common scenarios, the protocol's modular design enables the addition of new security types as market needs evolve.
The top US securities law firms came together to create the Open Captable Format (OCF) [5][6]. For the first time, an industry-backed standard emerged for representing capitalization data, marking a pivotal shift toward commoditization of cap table management. This wasn't just another technical specification—it was the industry's top legal minds agreeing on a) how to represent every aspect of private company ownership and b) how to bring capitalization data control back to the stakeholders, after years of virtual lockup by SaaS cap table vendors.
The Saas cap table platforms ended up joining the coalition, implementing capitalization data import and export functions using this new standard format. This effectively enables companies to maintain ownership of their data regardless of which service providers they choose. Law firms can verify cap tables using standardized tools. Most importantly, the industry has a common language for representing ownership—from simple common stock issuances to complex convertible instruments with specific rights and preferences.
Recognizing OCF's transformative potential early, we became participants in the initiative, giving technical feedback and porting the standard onchain. Enabling OCF as both a data standard and a foundation for programmatic equity operations.
Traditional cap table systems use mutable records that update share counts and ownership directly, the protocol enforces an immutable event log that captures the complete history of a cap table. Each operation generates specific events that are appended to this log, creating a verifiable chain of transactions. When shares are issued, for example, the system doesn't simply update a number—it records an issuance event containing quantity, price, stakeholder details, and associated terms.
The transaction system implements distinct event types for each cap table operation:
● Investment Operations: Convertible security events record investment amounts, conversion terms, and seniority relationships. When conversions occur, the system generates linked events showing the relationship between the original investment and resulting stock positions.
● Stock Operations: Events capture issuances, transfers, and cancellations, recording share quantities, prices, and stakeholder details. Each transfer maintains the link between source and destination positions, enabling complete ownership tracing.
● Compensation Events: Option grants, vesting events, and exercises are recorded with their specific parameters. The system maintains connections between grants and their stock plans, tracking how each grant affects the overall share pool.
Traditional offchain cap tables are plagued by inefficiencies—manual reconciliation, fragmented records, and opaque ownership tracking. In contrast, this event-driven architecture eliminates these frictions. Every state change is programmatically verifiable, removing the need for manual reconciliation. The complete audit trail allows ownership to be verified at any point by replaying events, ensuring transparency. Regulatory compliance is also strengthened through immutable record-keeping, reducing errors and disputes inherent in offchain systems.