Replication data for: Beware the middleman: Empirical analysis of Bitcoin-exchange risk

Bitcoin has enjoyed wider adoption than any previous crypto-currency; yet its success has also attracted the attention of fraudsters who have taken advantage of operational insecurity and transaction irreversibility. We study the risk investors face from Bitcoin exchanges, which convert between Bitcoins and hard currency. We examine the track record of 40 Bitcoin exchanges established over the past three years, and find that 18 have since closed, with customer account balances often wiped out. Fraudsters are sometimes to blame, but not always. Using a proportional hazards model, we find that an exchange's transaction volume indicates whether or not it is likely to close. Less popular exchanges are more likely to be shut than popular ones. We also present a logistic regression showing that popular exchanges are more likely to suffer a security breach.

比特币（Bitcoin）是目前应用最为广泛的加密货币（crypto-currency），但其成功也吸引了利用其运营安全漏洞与交易不可逆性特征的欺诈者的注意。本文研究了投资者在比特币交易所面临的风险——这类交易所负责比特币与硬通货之间的兑换业务。我们调研了过去三年间设立的40家比特币交易所的运营记录，发现其中18家已关停，且投资者的账户余额往往随之清零。欺诈行为有时是此类关停事件的诱因，但并非全部原因。通过比例风险模型（proportional hazards model）分析，我们发现交易所的交易量可用于预判其关停概率：相较于热门交易所，冷门交易所的关停风险更高。我们还通过逻辑回归（logistic regression）分析证实，热门交易所更易遭遇安全入侵事件。