Citation

Wang, W., Saraf, A., Heimbach, L., Babel, K., Zhang, F. “Blockspace Under Pressure: An Analysis of Spam MEV on High-Throughput Blockchains.” arXiv:2604.00234v1 [cs.GT] (Mar 31, 2026). Yale University / Cornell University / Category Labs. IC3.

Core Contribution

First principled theoretical framework for spam MEV on high-throughput chains, with empirical validation from Base and Arbitrum. Derives equilibrium spam volumes as a function of block capacity, minimum gas price, and fee mechanism.

Empirical Facts

  • Base and Optimism, Q1 2025: spam MEV >50% of block gas
  • Only 6–12% of spam probes result in actual trades
  • Spam transactions pay <25% of total fees despite consuming >50% of block gas
  • Empirical timing: spam grew sharply when block capacity was scaled up; fell when minimum gas prices were introduced

Theoretical Model

Setting: spam transactions compete for on-chain opportunities under competitive equilibrium that drives their profits to zero.

Equilibrium spam volume = f(block capacity C, minimum gas price g_min, fee mechanism)

Three Main Results

Result 1: Spam is always costly

  • Scarce blockspace: spam displaces legitimate users → drives up gas prices
  • Abundant blockspace: spam consumes execution resources → raises node externality (provisioning/processing cost)
  • Key insight: spam takes an increasing share of each marginal unit of capacity added
  • Capping capacity before all users are included: forgoing small user welfare eliminates disproportionate spam + externality

Result 2: Priority fee ordering reduces spam

  • FCFS (First-Come-First-Served) gives spammers equal access to any block position
  • Priority fee ordering forces spammers to bid for early positions → raises effective cost
  • Result: spam equilibrium volume falls; more of the spam budget goes to fees rather than tx count

Result 3: Spam share plateaus as demand grows

  • As user demand grows and blockspace scales proportionally, spam’s share of capacity stabilizes
  • Spam doesn’t grow indefinitely — bounded by profitable opportunity density

Why Spam Isn’t Fully Eliminated

Even with priority fees:

  • Spam transactions set priority fee = minimum viable bid
  • As long as expected profit from a lucky probe > minimum fee, spam remains equilibrium
  • The equilibrium is profitable for individual spammers while being socially costly

Policy Implications

Design choiceEffect on spamEffect on users
Scale block capacityIncreases spam volumeIncreases user inclusion
Introduce minimum gas priceReduces spamSlight cost increase for cheap txs
Switch FCFS → priority feeReduces spam volumeNormal MEV dynamics
Introduce encrypted mempoolMay increase spamProtects against targeted frontrunning

Encrypted mempool paradox: if encrypted mempools prevent searchers from observing opportunity signals, they probe more blindly → spam increases. This is confirmed by the model.

Connection to Existing Wiki

The Spam MEV: Probabilistic Block Space Extraction on High-Throughput Chains concept page synthesizes this paper with . This paper provides the equilibrium theory and empirical validation.