Market Fragmentation in Digital Assets

View Slides & Handout on Zenodo

This post is based on a seminar I gave at the Nanyang Technological University on February 4, 2026.

Fragmentation is the quality of concentration of liquidity. The concept measures the degree to which liquidity is dispersed across multiple venues and microstructures. In an idealized scenario with no fragmentation, all liquidity would be concentrated with a single counterparty at the best available price. In practice, fragmentation represents the degree of deviation from this ideal state. Importantly, fragmentation is not a temporary phenomenon but rather a structural parameter of financial markets.

Three dimensions of fragmentation

Fragmentation has three overlapping dimensions. A single market phenomenon can exhibit fragmentation on multiple axes simultaneously.

Horizontal fragmentation. Is the deal flow shared? Same asset, multiple venues. This is a widely studied and empirically quantified form of fragmentation, largely because it is straightforward to measure and has identifiable microstructure effects. Empirical evidence on whether horizontal fragmentation increases or decreases overall liquidity remains mixed, suggesting that the relationship is complex and context-dependent.

Vertical fragmentation. Is liquidity accessible under the same microstructure? Different cost and friction regimes (fees, tick size, credit requirements). Rather than liquidity being distributed across different exchanges, vertical fragmentation reflects segmentation of liquidity within an exchange due to different cost and access regimes.

Temporal fragmentation. Is liquidity available at the same time? Liquidity varies through time (timezone, session overlaps, settlement cycles). Although digital asset markets operate 24/7 globally without formal trading hours, regional activity patterns contribute to temporal fragmentation.

CEX vs DEX

In traditional finance, centralized exchanges dominate. The digital asset market features both centralized exchanges (CEXs) and decentralized exchanges (DEXs) operating simultaneously.

CEXs operate as custodial platforms: users deposit their digital assets to the exchange's wallets, and the exchange operator manages order matching and trade execution. All trading occurs off-chain in the exchange's database. A unique feature of CEXs is their ability to facilitate fiat-to-crypto conversions, giving them a structural advantage in onboarding new market participants.

DEXs rely on automated market makers (AMMs) rather than order books for price discovery and trade matching. An AMM is a smart contract that facilitates trading by maintaining liquidity pools and using a predefined algorithm to price assets. Prices in DEXs are determined algorithmically based on the reserves within liquidity pools rather than through traditional order book mechanisms.

Measuring fragmentation: the Fragmentation Efficiency Index

When reliable data are available, an entropy-based measure of liquidity distribution can quantify fragmentation. Let $m_i$ be the market shares of $N$ distinct venues as the proportion of total trading volume for a given asset, such that $\sum_i m_i = 1$. The Fragmentation Efficiency Index (FEI) is:

$$FEI = -\frac{1}{\ln N} \sum_{i=1}^{N} m_i \ln(m_i)$$

The original definition by Lehalle and Laruelle includes a scaling factor of $1/\ln(N)$ to normalize the index between 0 and 1. A low FEI indicates high liquidity concentration in a few venues; a high FEI indicates dispersed liquidity.

For Ethereum on February 1st, 2026, with $N = 6$ venues above $100M daily volume, the FEI was approximately 0.30, indicating high concentration (Binance held 86.6% of volume).

Implications

Price discovery. Horizontal fragmentation creates lead-lag relationships as information propagates across venues at different speeds due to network latency. Vertical fragmentation influences price discovery through information leakage between fee tiers or credit-line pools. Temporal fragmentation means settlement times affect price discovery: on-chain finality delays create uncertainty in trade execution and price convergence.

Arbitrage. Fragmentation enables arbitrage across horizontal (same asset, different venue), vertical (fee-tier or credit-line differences), and temporal (lead-lag between geographic hubs) dimensions. A persistent example is the ~2% Upbit premium ("Kimchi premium"), which persists due to Korean capital controls limiting arbitrage capital flows. Arbitrage is constrained by transaction fees (exchange, gas, bridge) that can exceed the arbitrage spread, capital constraints and position limits, and execution risk where prices may move before completion.

Fragmentation as optionality. While fragmentation increases costs, it provides strategic advantages. Different venues offer different microstructures, pricing mechanisms, and liquidity pools, allowing participants to optimize venue selection based on order type, size, and time horizon. DeFi offers distinct features: settlement guarantee through on-chain execution, anonymity on some DEXs, cross-chain liquidity aggregation via bridges and wrapped tokens, and liquidity provision across fragmented venues and fee tiers.

Practical heuristics

• Order size. Fragmentation becomes more relevant for orders that exceed top-of-book liquidity on a single venue. Large orders require smart order routing or slicing across venues.
• Persistent spreads. Price discrepancies that persist across venues typically reflect real frictions (capital controls, settlement delays, custody constraints, or latency) rather than exploitable arbitrage. Identify the barrier before committing capital.
• Venue selection. Choose CEX venues for speed and tight spreads on moderate-sized orders; choose DEX venues when settlement guarantee and on-chain transparency are priorities.

Key takeaways

• Fragmentation across horizontal, vertical, and temporal dimensions is a feature of digital asset markets;
• While fragmentation creates execution challenges, it also provides strategic opportunities for informed participants;
• Understanding fragmentation structure is important for designing effective trading strategies and liquidity provision approaches.

Fragmentation = Opportunity. Fragmentation creates inefficiencies that informed participants can exploit through smart execution, risk management, and strategic positioning.

The lecture slides and handout are available on Zenodo.