The year 2022 witnessed remarkable advancements in the realm of cryptocurrency infrastructure. Blockspace, the foundation of blockchain technology, has become more affordable, plentiful, and interconnected than ever before. Zero-knowledge technology continues to revolutionize scalability, transaction security, and user privacy. The Ethereum Merge stands as a testament to the power of well-designed economic incentives in seamlessly orchestrating major technical upgrades without disrupting the end-user experience.
Within this landscape of infrastructure innovation, order flow auctions stand out as a particularly exciting development. Order flow auctions (OFAs) serve as the financial backbone of the cryptocurrency ecosystem, orchestrating a diverse array of stakeholders to efficiently route transactions from their point of origin, such as a user's wallet, to their ultimate inclusion in the blockchain. Along this transaction journey, OFAs identify and extract inefficiencies, often referred to as "maximal extracted value" or MEV. The more intricate the transaction routing, the greater the potential for capturing substantial MEV opportunities.
This article delves into a particularly nascent category within the realm of OFAs: cross-domain markets. Cross-chain OFAs present unique challenges due to the asynchronous nature of blockchains. When two chains finalize blocks at different intervals, transactions between them inevitably encounter latency. This delay leads to suboptimal execution, increased opportunities for MEV extraction, heightened centralization risks, and amplified market inefficiencies.
Currently, two primary approaches have emerged to address the asynchronicity challenge in cross-chain OFAs: slot auctions and pricing premiums. Both approaches aim to mitigate the friction arising from blockchains operating at different block speeds. However, they diverge in their methodology. Slot auctions attempt to synchronize the chains, while pricing premiums rely on buyers' ability to determine an appropriate price to ensure transaction finality on both chains during the latency period.\
The majority of existing OFAs operate as block auctions. In this model, builders compete by submitting bids that represent their proposed block constructions, essentially vying for the right to have their block included as the next one in the blockchain. The objective of each builder is to construct the most profitable block, taking into account all available information, such as the transactions awaiting confirmation in the mempool and the current state of the blockchain. These auctions are characterized as just-in-time auctions due to their occurrence immediately before the block's inclusion in the chain.
In contrast to block auctions, slot auctions offer a distinct approach, auctioning off the right to construct a block at a predetermined future time. The key distinction lies in the absence of a pre-commitment to block contents when purchasing the slot. Notably, slot auctions encompass block auctions within their framework. Slots can be reserved or purchased as "blank" slots, allowing for just-in-time auctions to occur at a later point.
A significant advantage of slot auctions is the expansion of potential auction participants. The following examples illustrate different buyer personas and their motivations for engaging in slot auctions:
App layer projects: An NFT project might purchase slots well in advance of a mint to increase the likelihood of successful transaction execution, thereby enhancing the user experience.
Builders: Builders may be motivated to purchase slots to pursue multi-block MEV opportunities, leveraging their ability to influence block construction over multiple blocks.
Traders: Traders seeking to execute large cross-chain transactions might purchase slots to secure priority and minimize slippage.
These examples highlight the diverse range of participants and motivations that slot auctions can accommodate, potentially leading to a more vibrant and competitive market.
Pricing mechanisms offer an alternative approach to address asynchronicity in cross-chain blockspace markets, leveraging price as a tool to enhance the likelihood of successful transaction execution.
In contrast to slot auctions, which aim to synchronize chains, pricing mechanisms acknowledge the inherent difference in finalization times between chains and seek to determine the price at which a bidder is willing to pay to ensure transaction finality on the second chain, given that the transaction has already been finalized on the first chain. These mechanisms function as just-in-time auctions, where the first step involves securing execution on the first chain, followed by paying a sufficient premium to guarantee finality on the second chain.
The challenge lies in determining the appropriate price to pay. For an arbitrageur to profit, the cross-chain MEV gains must exceed the combined bids on both chains. Consequently, the maximum bid they should be willing to pay on the second chain is the anticipated profit minus the cost incurred on the first chain (0 < bid < arbitrage profit – cost on the first chain).
Interestingly, this market structure appears to favor chains with later finalization times. It mirrors the holdout problem in economics, where completion hinges on the holdout, and in this context, the second chain (or the last chain in a multi-chain scenario) assumes the role of the holdout. Consequently, validators on the final chain to finalize hold the most advantageous position for extracting profit.
This raises a series of intriguing questions: How should bidders determine their bid for execution on the first chain, considering the likelihood of higher costs on the second chain? Under what circumstances is a pricing mechanism preferable to slot auctions? How does the variation in finalization time gaps impact the pricing auction? What new centralization risks does this introduce? And many more.
It's important to note that cross-chain pricing mechanisms and slot auctions can, and likely will, coexist. Pricing mechanisms fill the void during periods of asynchronicity between chains, addressing a problem domain beyond the scope of slot auctions. As a result, cross-chain pricing mechanisms are poised to remain an exciting area of innovation in the months and years ahead.
Cross-chain blockspace markets hold a unique position in the evolving crypto landscape, as they represent both an inevitable progression and an uncharted territory. We're witnessing the maturation of new blockchains, both at the L1 and L2 levels, and anticipate the emergence of even more, such as L3s. Bridges are becoming more sophisticated, and applications are embracing a multi-chain approach. Given that blockspace forms the bedrock of the ecosystem, novel market structures like cross-chain markets introduce transformative dynamics across the entire stack. As cross-domain blockspace markets mature, we can expect to see shifts in market dynamics in several ways:
Heightened competition among blockchains for transaction volume: As cross-chain transactions become more seamless and efficient, blockchains will face increased competition to attract and retain transaction volume. This could lead to a race to provide the most attractive blockspace pricing and user experience.
Emergence of new pricing models for blockspace: Cross-chain markets may give rise to innovative pricing models for blockspace, potentially incorporating factors like transaction priority, latency requirements, and cross-chain arbitrage opportunities.
New market participants and roles: Cross-chain markets could attract new players, such as specialized cross-chain arbitrageurs and liquidity providers, who will play a crucial role in facilitating efficient cross-chain transactions.
Redistribution of MEV profits: The dynamics of MEV extraction could shift as cross-chain markets mature, potentially leading to a redistribution of profits among different stakeholders, including builders, arbitrageurs, and validators.
New centralization risks: While cross-chain markets offer significant benefits, they also introduce new centralization risks. For instance, entities that control critical bridging infrastructure could exert undue influence over transaction flows and pricing.
Impact on application development: Cross-chain markets could influence the design and development of decentralized applications, as developers consider factors like cross-chain transaction costs and latency in their application architecture.
Evolution of regulatory landscape: As cross-chain transactions become more prevalent, regulators may need to adapt their frameworks to address potential concerns around cross-chain compliance and consumer protection.
The development of cross-domain blockspace markets is poised to reshape the crypto ecosystem, introducing new opportunities, challenges, and dynamics that will shape the future of blockchain technology.
The journey of blockspace markets is just beginning. With each evolutionary phase, new elements emerge on the design frontier: novel forms of capital formation, such as NFTs, have given rise to new MEV opportunities, while the Ethereum Merge introduced proposer-builder separation, defining a distinct stakeholder group. As multi-chain applications gain traction, we can expect the development of more sophisticated mechanisms for internalizing MEV.
Blockspace markets hold immense potential to transform the crypto landscape, fostering a more efficient, transparent, and equitable ecosystem for all participants. As these markets continue to mature, we can anticipate a future where blockspace allocation and pricing are optimized to serve the needs of both users and builders, unlocking the full potential of blockchain technology.