It seems appropriate to recall a fatwa issued two years ago (2008) by the eminent Libyan Maliki legist (faqih), Sh Dr Sadiq al-Ghiryani. (According to some reports, Sh Sadiq was recently detained by the Libyan gov't and went underground when he was released in order to escape further mistreatment.) In the fatwa in question, Sh Sadiq states that the popular form of Rotating Saving and Credit Association (ROSCA, known in Arabic-speaking lands as "jam`iyya") is permissible. ROSCAs, though practiced with various variations, essentially work as follows: a group of people come together and agree to each contribute money to the group fund (the 'pot') periodically (say monthly) and then loan the total pot to one of the members periodically (monthly) until every member has had a turn.
Of particular interest to students of fiqh is Sh Sadiq's inclusion, at the end of his fatwa, of an explicit statement from a well-known Shafi`i commentary on the permissibility of exactly such a scheme. He says:
In Hashiyat al-Qalyubi `ala l-Minhaj [a well-known Shafi`i commentary] there is an explicit text (nass) on this issue (stating) that it is permissible. (The author of the Shafi`i commentary) dubs it "womens' Friday" [or "women's gathering"] (jumu`at al-nisa') and says: ''The well-known gathering (jumu`ah) among women in which a woman takes a certain amount from each memeber of the group, every Friday or (every) month, and then hands it to one (of them) after the another, until (money has been given to) the last of them, is permissible, as stated by (the Shafi`i authority) al-Wali al-`Iraqi (Hashiyat al-Qalyubi 3:321).
It should be noted that other contemporary fuqaha' hold a similar opinion. It is also noteworthy that the aforementioned Shafi`i text explicitly mentions a form that was practiced among women: pre-moderm Shari`ah- compliant informal micro-finance indeed!