In the most populous counties of the United States, approximately 60% of defendants arrested on a felony charge are released prior to the disposition of their case. Pretrial release in U.S. courts is influenced by the presence of commercial bond agents who provide a service of releasing defendants in exchange for a fee and assurances that defendants will make all court appearances. An arrested defendant can also be released through non-financial means including a release on own recognizance or release through a pretrial monitoring program. Recent studies have shown that commercial bond agents have become the most prevalent form of pretrial release offered to felony defendants in courts located in highly populous jurisdictions. The growth of the commercial bond industry raises questions about the effectiveness of this type of pretrial release in preventing missed court appearances. How do commercial bond agents compare with other forms of pretrial release in ensuring that released defendants make all court appearances and do not become fugitives? Prior research shows commercial bond agents doing better at preventing missed court appearances compared to non-surety release alternatives. Most of this research, however, does not address why surety agents excel at preventing missed court appearances. Defendants released through surety bond might skip court less frequently because they are being monitored more effectively compared to other forms of pretrial release or because surety agents have the capacity to select defendants who are most likely to make their court appearances. This paper engages in a preliminary exploration of whether monitoring practices or selection effects accounts for the efficacy of surety bond by examining defendants released in counties where surety agents are involved in nearly all facets of the pretrial release decision against a set of counties where surety agents play little to no role in pretrial release. Results provide mixed evidence suggesting that both monitoring capacity and selection effects account for the performance of surety agents at getting their clients back to court.