Native American tribal organizations are expanding their investment horizons.

During the past 20 years, several tribes in the U.S. have amassed fortunes, thanks mainly to gambling revenue. Now, their leaders are engaging with financial advisers to create portfolios of investments in financial markets and businesses that they hope will ensure reliable sources of income for future generations. Tribal organizations are making inaugural forays into stocks, hedge funds and acquisitions, shedding the conservatism of previous generations.

“There is now the willingness to take more of a risk,” says Dante Desiderio, executive director of Nafoa, formerly known as the Native American Finance Officers Association. He says tribal business models and investment philosophies have matured during the past two decades thanks to tribes’ experience in gambling, natural-resources development and the hospitality industry.

“We always relied on federal funds to make ends meet, and that’s never been enough,” says Mr. Desiderio, a member of the Sappony tribe, whose roots are in Virginia and North Carolina. “We have come a long way in a short period of time.”

Investing freedom

In the past, tribes didn’t have much of an opportunity to make risky investments, because their main source of funds was the federal Bureau of Indian Affairs, which restricts what can be done with the money it supplies. Money from the government can’t be invested in a way that puts principal at risk. And the investment of that money for the most part is managed by the government, which invests it mostly in Treasury securities.