Since the early 1990s, Islamic Microfinance Institution (IMFI) has become increasingly popular in many countries where the majority of the population is Muslim, especially in Indonesia (Rokhman & Abduh, 2020). Indonesia ranks first as the country with the largest Muslim population in the world. Based on data released by timesprayer as of July 3, 2025 (Timesprayer, 2025), the number of Muslims in Indonesia reached 245.3 million out of a total population of 282 million. Thus, it is not surprising that IMFI is growing rapidly in Indonesia.

IMFIs play an important role in the economy, but their competitiveness in the global market is still low. IMFIs have great potential in supporting the growth of Micro, Small, and Medium Enterprises (MSMEs) through sharia financing. IMFIs operate based on sharia principles that offer a fairer and transparent profit- sharing system, and avoid usury practices (Mubarrok et al., 2023). In Indonesia, most IMFIs are known as Baitul Maal wat Tamwil (BMT). BMT is a business organization whose role is to encourage investment and collaboration to create micro-enterprises and reduce poverty (Ajija, 2020) . BMT has two main functions, namely as baitul maal and baitul tamwil. Baitul Maal aims to collect and distribute social funds, such as zakat, infaq, and alms. While Baitul Tamwil is in charge of providing sharia financing services for customers, such as working capital financing, investment, and others (Huda & Heykal, 2010).

Although the majority of Indonesians are Muslims, the reality shows that IMFIs have fewer customers than conventional microfinance institutions. This is due to many factors, such as low Islamic financial literacy, suboptimal promotion, lack of variety of products and services offered and lack of public trust in IMFI. These factors pose a challenge for IMFIs to increase their presence and market share.

One of the major challenges faced by IMFIs in Indonesia is the low level of Islamic Financial Literacy (IFL) in the community. The 2025 Financial Services Authority (OJK) National Survey on Financial Literacy and Inclusion (SNLIK) revealed a significant gap in literacy levels between Islamic and conventional finance in Indonesia. Sharia literacy stands at 43.42%, while conventional literacy reaches 66.45%. This indicates that more than half of Indonesia's population (around 56.58%) do not fully understand sharia-based financial products and services (Sharia knowledge center, n.d.).

Based on the SNLIK data, it can be interpreted that the increase in IFL, the greater the understanding and knowledge of the community towards Islamic financial principles, products and services, so that more people decide to use the products and services of Islamic financial institutions, including IMFI. The study of Albaity & Rahman (2019) corroborates this statement that IFL has a direct effect on the interest in saving 350 prospective Islamic bank customers in the UAE. The study of Suwarsi et al (2022) also supports the above research results that IFL has a positive and significant impact on business development in 1392 MSMEs in Yogyakarta, Indonesia. The same thing is also proven by the study Fauzi & Murniawaty (2020) which states that IFL owned by students affects the interest in saving in Islamic banks. However, in contrast to some of the research above, the study of Mulyaningtyas et al (2020) revealed that financial literacy has no impact on students' interest in saving at Islamic banks in Malang City.

Another factor that can influence customer saving interest is promotion. With promotion, marketers can inform, persuade, and remind potential customers about IMFI products and services to influence customer opinions. The study Malik et al (2021) proves that promotion has a big impact on public interest in saving at BSI KCP Singkut in the village community Pelawan Jaya, Jambi. However, the study of Majhaf (2020) shows different results that promotion has no impact on people's interest in saving at Bank Muamalat Indonesia Palu, Central Sulawesi.

In addition to IFL and promotion, product quality and customer trust are important aspects that can increase people's preference in using IMFI services. The study of Hardana et al (2022) confirms that product quality has a large and favorable impact on saving interest in BSI Padangsidimpuan Branch. However, in contrast to the above study, according to Ulya et al (2020) , the relationship between product quality and saving interest is not significant. Regarding the aspect of customer trust, the study of Nurrohmah & Purbayati (2020) proves that trust has a positive and significant effect on interest in saving in Islamic banks. But on the contrary, the study Aziz & Hendrastyo (2020) revealed that the interest in saving in Islamic banks Ulak Karang Branch, Padang City is not influenced by customer trust.

Based on the review of previous research above, there are still gaps in research results regarding the factors that influence interest in saving at Islamic financial institutions. Previous research emphasized the significance of IFL Albaity & Rahman (2019; Suwarsi et al., 2022; Fauzi & Murniawaty, 2020) , promotion (Malik et al., 2021) and product quality (Hardana et al., 2022) in increasing interest in saving. However, the study of Mulyaningtyas et al (2020; Majhaf, 2020; Ulya et al., 2020) shows different research results. Therefore, this study seeks to fill this gap by examining the effect of IFL, promotion and product quality on saving interest with customer trust as an intervening variable at IMFIs in Central Java. Hopefully, the results of this research can develop a more comprehensive model of customer acceptance behavior towards IMFIs.

The research population is all IMFI customers in Central Java, Indonesia. In PLS-SEM analysis modeling, the minimum recommended sample size is 5 times the number of indicators used to measure a construct or 5-10 times the number of parameters estimated (Ferdinand, 2014; Hair et al., 2020). For this reason, the sample selected was (n = 170) IMFI customers using accidental sampling technique. The measurement of questionnaire items was adapted from previous research and slightly modified to fit the context of IMFI. The following table describes the research questionnaire lattice.

The PLS-SEM results in this study investigate the effect of IFL, promotion and product quality on customer trust. The results of table 5 show that IFL (t- statistics = 3.005, p = 0.003) and PQ (t-statistics = 7.472, p = 0.000). These results show that the t-statistics values of 3.005 and 7.472 > the t-table value of 1.96 and the p values of 0.003 and 0.000 < 0.05, hence there is sufficient evidence that H1 and H3 are supported. Unfortunately, H2 which examines the effect of promotion on customer trust is not statistically significant as indicated by P (t- statistics = 0.679, p = 0.498).

Furthermore, H4, H5, H6 and H7 test the effect of IFL, promotion, product quality and customer trust on saving intention. The results of table 5 show that IFL (t-statistics = 3.012, p = 0.003), P (t-statistics = 4.255, p = 0.000), PQ (t-statistics = 2.173, p = 0.030), and CT (t-statistics = 3.079, p = 0.002). Therefore, it can be concluded that all hypotheses are supported. Meanwhile, H8, H9 and H10 examine customer trust in mediating the effect of IFL, promotion and product quality on saving intention. The PLS-SEM results indicate that IFL (t-statistics = 2.218, p = 0.027) and PQ (t-statistics = 2.789, p = 0.006). Thus H8 and H10 are statistically significant at 5 percent alpha, hence H8 and H10 are supported.

Unfortunately, H9 is not significant as indicated by P (t-statistics = 0.649, p = 0.516).

The findings of this research prove that Islamic Financial Literacy (IFL), promotion and product quality are important aspects that trigger customers' interest in saving at Islamic Microfinance Institution (IMFI). This is indicated by the PLS-SEM results that the structural model built in this research indicates a "moderate" model. This research contributes to developing aspects of Islamic Financial Literacy (IFL) so that a more comprehensive model of the behavior of using products and services at IMFI is built.

The results of this study successfully prove that IFL has a significant influence on customer trust and saving intention. The higher a person's IFL level, the stronger their trust in IMFI, which in turn encourages them to make wise financial decisions, including choosing products and services at IMFI. The findings of this research provide a strong basis that improving Islamic financial education is a necessity, not an option. Currently, the main obstacles to the development of Islamic Financial Literacy (IFL) are minimal education and poorly understood Islamic financial products. Islamic financial education is still uneven and has not reached all levels of society. People often see sharia products only as 'conventional alternatives' with Islamic frills or consider them exclusive to certain circles. They may not fully understand the essential differences between murabahah, mudharabah, musyarakah or ijarah and conventional bank loans or stock investments in general. Therefore, there needs to be a collective effort involving the government, regulators, Islamic financial institutions, academics, and community leaders in designing Islamic financial education programs that are more massive, accessible, and relevant to the needs of the community.

The findings of this research support the results of previous research which suggests a direct effect between IFL and Islamic bank customers' saving interest in the UAE (Albaity & Rahman (2019) . The study Fauzi & Murniawaty (2020) states that IFL owned by students affects the interest in saving in Islamic banks. Even a high level of IFL has a positive and significant impact on business development ( Suwarsi et al., 2022) . Thus, improving Islamic financial literacy is an important foundation to encourage Islamic financial inclusion and empower people to make smarter and shar'i financial choices.

PLS-SEM results show that promotion has a significant effect on interest in saving at IMFI. The more attractive the promotion of products and services offered by Islamic financial institutions, the higher the interest in using these Islamic financial products and services. The results of this study support the findings of previous research which states that promotion triggers a positive and significant influence on public interest in saving in Islamic banks (Malik et al., 2021; Aziz & Hendrastyo, 2020). However, the research also found that there is not enough evidence to support promotion as an important factor influencing customer trust in Islamic microfinance institutions. It is suspected that the lack of support for the second hypothesis is due to ineffective and optimized promotion, resulting in a lack of customer awareness and trust in IMFIs. Some people may still doubt the reliability and security of Islamic microfinance institutions. This could be due to previous negative experiences, lack of clear information, or the perception that Islamic financial institutions are less modern or flexible.

The PLS-SEM results also found that product quality has a significant effect on customer trust and interest in saving at IMFI. This is in line with the findings of previous research from Prasetya et al (2017) which states the relationship between product quality and trust. Furthermore, Hardana et al (2022) also shows a positive and significant effect of product quality on saving interest. The better the quality of products and services of Islamic financial institutions, the higher the trust and interest of customers in using these Islamic financial products and services.

Finally, the PLS-SEM results found that customer trust acts as a mediating variable in the influence of IFL and product quality on saving intention at IMFI. Trust is an important aspect that drives interest in saving at Islamic microfinance institutions. This is in line with the support of previous research from Nurrohmah & Purbayati (2020) which states that there is a positive and significant relationship between trust and interest in saving at Islamic banks. The study of Prasetya et al (2017) found a significant influence between product quality on trust . In addition, the significant influence between customer trust and saving intention has also been explained in the study of Nurrohmah & Purbayati (2020). However, the results also found that there is not enough evidence to support customer trust as a mediator in the effect of promotion on saving intention in IMFI. Therefore, Islamic microfinance institutions must pay serious attention in their efforts to strengthen customer trust to increase customer interest in using Islamic financial products. This is because building trust takes a relatively long time and can develop after repeated meetings with customers.

This study aims to reveal the factors that trigger customer trust and interest in using Islamic financial products at the Islamic Microfinance Institution (IMFI). This study found empirical evidence of the significant influence of Islamic Financial Literacy (IFL), promotion and product quality on saving interest. The research findings also found a positive and significant relationship between IFL and product quality on customer trust. However, promotion was found to have no impact on customer trust. The mediating role of customer trust is evident in the effect of IFL and product quality on saving interest, but not proven with promotion.

Based on the findings of this research, practitioners of Islamic financial institutions need to take several strategic steps, such as: increasing Islamic financial literacy, optimizing promotions, developing innovative products and services, and building customer trust. Attractive promotions can be done by using various media and targeting the right target audience. In addition, building customer trust can be done by increasing transparency in operations, providing excellent service, and maintaining the reputation of Islamic microfinance institutions.

Last but not least, there are several aspects of this research that can be recommended for future research agendas. First, further research is recommended to use a larger sample size and involve various industry parties to improve the quality and representation of the research results. Larger samples tend to provide more precise estimates and facilitate the generalization of research results to a wider population. The involvement of various industry parties will also enrich perspectives and ensure the relevance of research findings to industry needs. Second, this research uses Theory of Reasoned Action (TRA) as the grand theory. For this reason, further research is recommended to consider more sophisticated consumer behavior theories, such as Theory of Planned Behavior (TPB) or Theory of Interpersonal Behavior (TIB), which are developments of TRA. Third, this research design uses PLS-SEM analysis techniques. For future researchers, we recommend adding new constructs, in addition to Islamic Financial Literacy (IFL), promotion and product quality because PLS-SEM is very appropriate for research that aims to develop theory.