Let’s start with some billionaire math.

Some 2000 ultra-wealthy households in the United States each hold more than $500 million in assets. This deepest-pocketed demographic controls about $3.7 trillion dollars. In 2017, these wealthiest of Americans donated about $45 billion to charity, translating into an annual charitable giving rate of about 1.2% of their assets. Meanwhile, the vast assets of those same individuals likely grew at a rate that matched or exceeded the S&P 500’s 9% average rate of return over the past 20 years.

“Wealth is piling up and people are not giving as fast as they might,” says Sue Merrilees , a senior advisor with the Science Philanthropy Alliance, a Palo Alto, California-based nonprofit philanthropy advisory group. The Alliance was established in 2013 to help those of considerable means — often known in this sphere as high net worth individuals (HNWI) — give in ways that further scientific causes they care about.

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