This thesis examines three distinct topics on settlement microstructure and market efficiency in both DeFi and TradFi. Chapter one introduces the thesis’ unifying lens, arguing that settlement microstructure drives market efficiency across these markets. It links the three papers by showing how access in Bitcoin private channels, timing in Ethereum intertemporal gas hedging, and composition in equity market retail participation jointly determine fees, latency, liquidity, and price discovery, while previewing the policy framework that renders these mechanisms legible, bounded, and measurable. Chapter two, based on the working paper “Private Settlement in Blockchain Systems” with Dr. Alfred Lehar, provides evidence that the settlement market in blockchain systems is not purely transactional and diverges from the predictions of a simple competitive auction model. Using data from the Bitcoin blockchain, we find that 5.88% of transactions, labeled as private, bypass the competitive auction and are routed directly to miners. Despite being more active than the average user, these transactions are consistently confirmed by a single miner, a statistically unlikely outcome in a competitive environment. Our findings suggest that high-demand users form long-term agreements with miners, paying, on average, 20% lower fees. This chapter also documents how such settlement contracts are structured and operate within an unregulated market. Chapter three, based on the working paper “Gas Tokens: Market for Future Settlement in the Ethereum Blockchain” with Dr. Alfred Lehar, examines the implications of gas tokens as a potential market for future settlement within the Ethereum network. We show that sophisticated and frequent users are more engaged in gas token markets, pre-purchasing tokens to hedge against fluctuations in gas prices and paying, on average, 15.25% lower settlement fees. Moreover, bots actively pursue arbitrage opportunities in gas token markets and hold substantial volumes. Our findings indicate that traded gas token prices have strong predictive power for future gas prices. This research contributes to the development of modern financial instruments for price discovery and hedging within the Ethereum network as a two-sided market. We also empirically analyze the implementation of the Ethereum Improvement Proposal EIP-1559 as a natural experiment. Chapter four, based on my working paper “Silencing the Noise: Amplified Effects, A Causal Study on Price Efficiency”, investigates the causal effects of noise trader removal on market liquidity. In September 2022, an unexpected internet disruption in Iran restricted noise traders while informed traders retained access through brokers. This disruption led to a 6.65-fold increase in the bid-ask spread and a 46.8% decrease in informed trade speed due to market access asymmetry. Social media censorship in affected regions further amplified information asymmetry, resulting in a 7.2% price impact. Using a five-year analysis of political unrest, this study disentangles the effects of unrest and internet disruption on noise trading activity. The findings reveal that political unrest increases regional noise trading activity, whereas internet disruption decreases it. When both unrest and internet disruption occur simultaneously, regional noise trading activity decreases by 23.5%. This paper provides novel insights into market microstructure and the dynamics of liquidity provision through noise trading in emerging markets.