Scholarly authorship confers recognition and prestige and is used for promotion and tenure. In this commentary, the authors discuss a form of guest authorship known as authorship commerce (AC). This is an extreme example of misconduct, linked to bribery, which is potentially underestimated because it is difficult to detect. Pressure to publish in high impact factor open access journals (with often high publishing fees), combined with funding policy constraints, can facilitate AC. Proactive solutions include giving junior researchers more awareness of the unethical behavior, explicit guidelines that forbit it, author declarations, ethical publication incentives and metrics, lower publishing fees, as well as more effective fee discount and waiver programs. Anonymous and protected whistleblowing channels can be used to report AC.