The Impact of Bulk Purchasing on Market Liquidity and,Speculation: An Empirical Study from OpenSea

Abstract

Non-fungible token (NFT) marketplaces are the main venues for NFT transactions. In recent years, these platforms have introduced ”Sweeping,” a bulk purchasing feature intended to improve the buying experience and enhance market liquidity. Although this feature offers clear benefits, such as simplifying the purchase of multiple NFTs and reducing gas fees, its actual effects on market dynamics remain underexplored. This study examines how the bulk purchasing feature affects two key dimensions of the NFT market, liquidity and speculation. Using a comprehensive dataset of Ethereum on-chain NFT transactions, NFT collection characteristics, and Twitter data, we adopt a rigorous identification strategy that combines Propensity Score Matching (PSM) with Difference-in-Differences (DID) estimation to identify causal effects. We find that the bulk purchasing feature significantly increases both liquidity (measured by transaction volume and sales count) and speculation (measured by price volatility and turnover rate) at the collection level. These results are consistent with Transaction Cost Economics (TCE). We also find heterogeneous effects. Collections with higher economic and social value experience larger gains in liquidity. In contrast, the effect on speculation remains similar across collections with different value attributes. These findings offer decision support for NFT marketplace operators seeking to design and implement bulk trading mechanisms.