Microfinance is a vehicle for providing financing, insurance and other related financial services to working poor individuals or families, entrepreneurs, and small businesses that do not have access to traditional sources for such financial services. The chief business of most microfinance companies is that of providing small loans, referred to as microloans or microcredit, typically in the range of just a few hundred dollars, to entrepreneurs or working poor in underdeveloped countries. Although some microfinance loans are made at interest rates substantially higher than average loan rates at traditional financial institutions, they provide necessary funding that is designed to help low-income or otherwise disadvantaged earners improve their economic positions.

In addition to microloans, microfinance institutions (MFI) also provide services such as microsavings and micro-insurance. Microsavings accounts allow individuals to deposit small amounts of money with a financial institution without minimum balance requirements. Micro-insurance, which ranges from products such as crop insurance all the way to life insurance, offers individuals the ability to obtain small insurance policies with correspondingly small premiums.

Some MFIs are nonprofit organizations, but an increasing trend has been toward the proliferation of profit-seeking MFIs that seek solid returns for investors. Even major banks such as Citigroup Inc. (NYSE: C) have entered the business of microfinancing.

Here are the five largest and most influential MFIs as of 2016.

51Give

Founded in 2007 in Beijing, 51Give provides microfinance solution services for other MFIs. The organization offers an e-commerce platform that offers both online and mobile technology designed to connect individuals, companies, organizations and institutions with local MFIs, thus facilitating donations, investments and the delivery of microfinancing services. As of 2015, 51Give's platform was being used by more than 100 charitable organizations.

Bank Raykat Indonesia

Bank Raykat IDR250 (BBRI.JK), also known as Bank Raykat Indonesia, is the oldest Indonesian bank, founded in 1896 in Jakarta, and has established itself as one the country's largest financial institutions, while operating primarily as a small-scale and microfinance lender, with more than 30 million retail banking clients conducting business with the bank through thousands of branches and rural service posts. The bank is 70% government-owned.

BRAC

One of the oldest existing MFIs is BRAC, founded in 1972 in Bangladesh. BRAC provides a broad range of services in the areas of human rights, education, health and economic development, including grants and small business loans, housing assistance and microsavings services. BRAC operates in a dozen developing countries, stretching from Haiti to the Philippines. As of 2015, its gross loan portfolio was more than $1.4 million.

Grameen Bank

Grameen Bank, founded in Bangladesh in 1983, holds the distinction of being a Nobel Peace Prize-winning MFI. It originated as a result of the work of its founder, Muhammad Yunus, whose research pioneered the concept of providing micro-banking services and non-collateralized loans for the poor in order to alleviate poverty. As of 2015, Grameen Bank has more than eight million borrowers and a loan portfolio in excess of $18 billion. In addition to providing microcredit and other banking services, the bank also launched an award-winning low-cost housing program in 1998.

Kiva Microfunds

Founded in 2005 and headquartered in San Francisco, Kiva Microfunds is a nonprofit MFI that operates in the United States and more than 80 other countries worldwide. Kiva's operational method for providing microfinance lending is through establishing a crowdfunding, or peer-to-peer (P2P) lending, platform that allows individuals to lend directly to borrowers in other countries who lack access to traditional financing sources. Kiva provides interest-free financing for small businesses, education and health services such as clean water. As of 2016, Kiva has extended more than $850 million in microloans, and has a network of approximately 1.5 million lenders and approximately two million borrowers. The organization's website states that it funds an average of $2.5 million in loans weekly.