One of the more interesting trends in philanthropy this decade is that the thick wall between the giving of foundations and the grantmaking of venture capitalists is breaking down.

Some donors still maintain walls between their grantmaking and their investments. Bill Gates has always done some investing on his own apart from the Bill and Melinda Gates Foundation. For example, he is the chair and major investor of TerraPower which is trying to construct “travelling-wave” nuclear reactors that they say are far safer than existing reactors. Peter Thiel, too, separates his philanthropic activity from his investing grantmaking (though some of the grants of the Thiel Foundation work as venture capital for young entrepreneurs).

The Ford and MacArthur Foundations have both announced dramatic increases in program-related investments made from their endowments.

But in the past few years, some donors have used as their vehicles for giving limited liability companies rather than foundations. The Chan Zuckerberg Initiative is an LLC rather than a nonprofit, as is the Omidyar Network.

Now Laura and John Arnold are joining the movement towards establishing LLCs. The news in the Arnolds’ case is that they have created a holding company to oversee their activities. According to Abby Schulz writing at Barron’s, the Arnolds are taking their foundation, their donor advised fund, and a political action group called Action Now Initiative and creating an umbrella organization surrounding them called Arnold Ventures.

I last wrote about the Arnold Foundation two years ago, when I noted that the Arnolds are very active donors and nearly all of their projects result from their very extensive reading.

The goal of Arnold Ventures, according to their website, is “to invest in evidence-based solutions that maximize opportunity and minimize injustice.” The new enterprise has four program areas: criminal justice reform, health policy, education, and “public finance,” including pension reform.

They are also strong believers in what they say is “evidence-based research,” and may be the only organization in America who employs someone whose title is “evidence-based policy analyst.”

Arnold Foundation president Kelli Rhee told the Chronicle of Philanthropy that one reason the Arnolds shifted to an LLC was because they weren’t creating change fast enough through grants to nonprofits and that they could make changes faster through an LLC.

“We have to be thinking about driving change at scale,” Rhee said. “We’ve come to the realization that we have always been and will always be about affecting policy change.

As Schulz notes, one thing the Arnolds can now do is use lobbying, investment in start-up enterprises, and grantmaking, depending on what they think is appropriate. They’re also donors who have gotten both liberals and conservatives mad at them. The left can’t stand the Arnolds’ efforts for curtailing public pension abuse (the National Public Pension Coalition has a website called “The Truth About John Arnold” which has an interactive map that shows grants from the Arnolds to organizations they don’t like). The right doesn’t particularly like the Arnolds’ support for Planned Parenthood and that the Arnolds say they are Democrats who raised money for Barack Obama.

Kelli Rhee told the Chronicle of Philanthropy that Arnold Ventures “will continue to hold ourselves to the highest standards of openness and transparency” and that becoming an LLC was not a way to hide their spending. She also said that Arnold Ventures would not do more impact investing than in the past.

The Arnolds’ most recent investment came in September, when, along with seven hospital systems, the Peterson Center on Healthcare, and the Gary and Mary West Foundation, they pledged $1 million and offered $9 million in credit to CivicaRx, a company that plans to use their $100 million in capital and credit to manufacture 14 generic drugs used in hospitals.

How will becoming an LLC affect the Arnolds’ grantmaking? My guess will be that the organization will become more flexible than the Arnold Foundation was, and that they will continue to make grants that will bother both liberals and conservatives.

“Our work is less about capital campaigns and building infrastructure, where you can say, ‘Here’s a dollar, and here’s the brick it built,’ John Arnold told Texas Monthly in December. “We’re more willing to take risks, to say, ‘Here’s a dollar, and there’s a chance it will have no impact. But there’s a chance it will have high impact.’”

“The fact that they’re so young and dedicated makes the Arnolds stand out in the philanthropy world,” Chronicle of Philanthropy editor Stacy Palmer told the Baltimore Sun. “They’re not the type of donors who want their names slapped on a building at a college. They give to advocacy.”

Remember: John Arnold is 45. Laura and John Arnold could remain very active donors for decades.