A version of this article appeared on Kiplinger.

If you’ve considered putting your money into an investment that produces financial results and social good, you might be an impact investor.  But there are a few things you should know about this rapidly growing movement.

Impact investments occupy various categories. For instance, there are socially responsible mutual funds in frontier, emerging or developed markets that qualify as impact investments. Those funds might exclude or include investments based on their potential for social harm, like tobacco or defense, or social good, like companies that hire marginalized workers or repair environmental damage. You can also make impact investments in private companies, such as through venture capital, crowdfunding or angel investing.

One of the resources for information is The Monitor Institute, a “next ideas” consultancy that offers best practices in public problem solving. It divides impact investors into two categories: financial-first investors and impact-first investors. Financial-first investors expect a market or above-market rate of return. Their primary concern is a healthy return on investment. Impact-first investors focus more on the social or environmental benefits of the fund or venture. Financial gains are secondary to the social impact of their investment. If you are an impact-first investor, you might be willing to accept a below-market rate of return, or simply a repayment of principal, if the investment has the potential for great social change.

Ratings service Morningstar Inc. has created a list of funds that meet criteria for social responsibility, including the Jensen Quality Growth Fund (JENSX), Amana Income (AMANX) and Amana Growth (AMAGX). Remember that a fund that did well in the past isn’t guaranteed to do well, financially or by social criteria, in the future.

If you become an impact investor, you will join a rapidly growing group. Impact investing, also known by its older name, socially responsible investing, has grown into a multibillion-dollar market over the past several years. Funds with a social focus are proliferating. The outlook remains bright.

Many impact investors think of their work as complementary to philanthropy – one more way of enacting positive change. “One of the biggest things I’ve learned in more than a decade of this work is that you really can make the world better in any sector – in nonprofits, in business, or in government,” Pierre Omidyar, founder of eBay and the Omidyar Network, has said. “It’s not a question of one sector’s struggling against another, or of ‘giving back’ versus ‘taking away.’ That’s old thinking. A true philanthropist will use every tool he can to make an impact.”

One of Omidyar Network’s earliest investments was in Ethos Water, a bottled water company that uses a share of their proceeds to improve access to clean water in developing nations. In 2014, private equity giant Bain Capital joined the impact investment market by acquiring a 50% stake in TOMS shoes, an ethical footwear company that has donated more than 10 million pairs of shoes to children in need.

The Gates Foundation is also at the forefront of the impact investment movement. The Foundation has allocated more than $1 billion to loan guarantees, low-interest loans, and equity investments in nonprofit organizations. In 2015, the foundation made a $52 million investment in CureVac, a pioneering biotechnology firm focused on developing low-cost drugs and vaccines for controlling the spread of infectious disease in underdeveloped countries.

J.P. Morgan and the Rockefeller Foundation’s Global Impact Investing Network (GIIN) expect the impact investing market to swell to $500 billion by the year 2020. Younger generations of investors, who came of age during the global financial crisis of 2007-08, seem especially keen to direct private capital into socially responsible investment funds.

GIIN outlined four characteristics of an impact investment, which helped generate the questions below. If you are considering becoming in impact or socially responsible investor, make sure you’ve asked these questions of yourself and about the particular fund or investment you’re considering.

1. What is your intention? The intent of the investor to generate social and/or environmental impact through investments is an essential component of impact investing.

2. Does the investment have a potential return? Impact investments, including impact investment funds, are expected to generate a financial return on capital and, at a minimum, a return of capital.  Impact investment funds often have higher expense ratios, so remember to take those into account.

3. How do the risk and return differ from what you would find in the market? Impact investments generate returns that range from below market (sometimes called concessionary) to returns that can equal or exceed the market’s, but with risk factors that differ from the market’s.

4. Is there good impact measurement available? A hallmark of impact investing is a commitment by the investment’s manager to measure and report the social and environmental performance and progress of underlying investments. Measurement helps ensure transparency and accountability, and is essential to build the field of impact investing.

We have yet to see the limits of the social change impact investing can make. The most pressing issues of our time – including climate change, education, poverty, clean water and healthcare – will not be resolved by a single group of people. It will require a concerted effort from multiple sectors to make progress against these urgent global crises.

Impacting investing offers many people a practical and sustainable way to give back to those around us. A CFP® professional can help you get started.