Purpose: This work proposes a research model that explains investment intention in online peer-to-peer (P2P) lending based on the persuasion theory of elaboration likelihood model (ELM). In the proposed model, investment intention indirectly relates to source credibility and argument quality through the mediation of trust. At the same time, the study hypothetically moderates the relationships between source credibility and trust and between argument quality and trust by financial self-efficacy and risk preference. Design/methodology/approach: This research presents an experiment to empirically validate its theoretical rationales. The hypotheses herein were tested using data from working professionals at a large science park in Taiwan. A total of 500 participants took part in the experiment in which the scenario of a pseudo-online P2P lending intermediary was first presented for their perusal, and then questionnaires based on the scenario were provided for the participants to fill out. Findings: Trust cannot be improved over night without making great efforts on source credibility and argument quality in the long run. Online marketers should study market segmentations to decide what appropriate elements and promises should be provided in advertisements in order to improve their source credibility. Moreover, how online intermediaries formulate convincing messages and Polish their delivery communication skills should be improved so as to increase argument quality. Originality/value: First, the theoretical conceptualization of source credibility and argument quality built upon the ELM not only broadens the boundary of virtual communities beyond the literature that considers source credibility and argument quality as important determinants, but also shows the practical status quo of trust as a critical mediator. Second, this research incorporates financial self-efficacy (based on social cognitive theory) and risk preference (based on economic theory) as important moderators in the development of trust. For that reason, customer education initiatives that influence financial self-efficacy and risk preference are discussed in greater detail.