What it means
The starting problem is exclusion. Someone with no salary slip, no credit file and no property to pledge cannot open a normal business account or borrow from a bank, even when they run a perfectly viable trading operation.
Microfinance institutions fill that gap with products sized for very small cash flows. That means loans of a few hundred dollars, savings accounts with no minimum balance, crop or health insurance sold in small premiums, and cheap ways to send and receive money.
For business readers the sector matters for two reasons. It is a genuine market in its own right, funded by development banks, social investors and increasingly commercial capital, and it is also the testing ground for a lot of the low-cost digital banking technology that later moves upmarket.
Microfinance institutions are measured on a distinctive set of ratios. Portfolio at risk over 30 days shows what proportion of the loan book has a payment more than a month late, and operational self-sufficiency shows whether income from lending covers the cost of running the business without subsidy.
The nuance worth knowing is that the sector has moved from a purely social framing to a mixed one. Commercial funding brought scale and discipline, but it also brought pressure to grow loan books quickly, which is why responsible lenders now put as much weight on client protection and total borrower indebtedness as on growth.
In practice
Real-world examples.
Example
A microfinance institution in an agricultural district pairs a $700 seasonal input loan with a simple weather insurance policy. When rainfall falls below a set threshold the policy pays out, so a bad season does not automatically become a default.
Example
A mobile network operator launches a savings and payments wallet with no minimum balance and instant transfers costing a few cents. Within two years several hundred thousand small traders use it to hold takings safely instead of carrying cash.
Example
A social investor reviews two lenders with identical loan books. One reports portfolio at risk over 30 days of 2.5% and the other 9%, and that single ratio drives the decision on where the next $5,000,000 of funding goes.
Formula
Calculation
A standard sustainability measure is operational self-sufficiency: OSS = Operating revenue / (Financial expense + Loan loss provision + Operating expense).
Consider a microfinance institution with a $9,000,000 loan portfolio. Over the year it earns $1,350,000 in interest and fees. Its costs are $300,000 of interest on wholesale borrowing, $135,000 of loan loss provisions, and $690,000 of salaries, branch and technology costs.
Total costs = $300,000 + $135,000 + $690,000 = $1,125,000. OSS = $1,350,000 / $1,125,000 = 1.20, or 120%.
Anything above 100% means the institution covers its own operating costs from its own revenue rather than relying on grants. At 120% it generates a $225,000 surplus, which it can use to absorb a bad year or to fund growth in the loan book.Case study
Seen in the real world.
Meridian Grameen Trust is a fictional institution used here as an illustrative case. It started as a grant-funded lender with an operational self-sufficiency ratio of just 68%, meaning it needed donor money to cover roughly a third of its running costs, and its board set a five-year target of full self-sufficiency.
The trust did three things: it added a savings product that gave it cheaper funding than wholesale borrowing, it moved repayment collection onto mobile phones and cut branch visits, and it raised average loan size modestly from $420 to $610 so that fixed costs were spread over more principal. Operating cost per borrower fell by about a third.
By year four the illustrative trust reported operating revenue of $1,350,000 against total costs of $1,125,000, an OSS of 120%, and it stopped taking grant funding for operations. The board kept a client protection review in place so that the drive for efficiency did not turn into pressure on borrowers to take larger loans than they could service.
Watch out
Common mistakes.
- Using microfinance and microcredit as synonyms. Microcredit is only the lending product, while microfinance also covers savings, insurance and payments, and the savings side is often what clients value most.
- Judging a microfinance institution on loan book growth alone. Rapid growth in a market with several lenders often means the same borrowers are being lent to twice, which shows up as arrears a year later.
- Assuming high interest rates prove exploitation. Cost per dollar lent is genuinely high at this loan size, so the meaningful test is the lender's operating cost ratio and profit margin, not the headline rate.
Questions
People also ask.
What is portfolio at risk?
It is the outstanding balance of all loans with a payment overdue beyond a set number of days, usually 30, expressed as a percentage of the total portfolio.
Can microfinance be profitable?
Yes, and many institutions run sustainably above 100% operational self-sufficiency, though returns are typically modest compared with commercial banking.
Does microfinance actually reduce poverty?
Evidence is mixed, showing reliable gains in business investment and household cash management but weaker evidence of large income increases, which is why most serious providers now measure client outcomes directly.
From the founder's library
Take it further with the book.
Build your financial confidence beyond this definition. Shihan's full-length guide, Accounting Fundamentals, takes the same plain-English approach and turns it into a complete, practical playbook for non-finance managers, business owners and students - with chapter-end quiz answers and presentation slides included.
25% off with code MMHQ25, applied at checkout. Priced in USD - checkout may show the equivalent in your local currency.
View the book and save 25%Related