Forbes reports on the investment strategy of billionaire hedge fund manager William Ackman. He makes money investing in charter schools and thinks he is “doing good” by undermining public education.

“It turns out that Bill Ackman is making good money in the most unexpected of places: financing charter schools for low-income kids.

“Since 2011, the billionaire hedge fund manager has invested $20 million of his own money in the Turner-Agassi Charter School Facilities Fund, which was started by former tennis star Andre Agassi and has built 79 new charter schools in poor neighborhoods around the country. The impact investment, which Ackman made via his charitable foundation, has netted annual returns north of 10%.

“Meanwhile, performance at his hedge fund has been languishing. Ackman has lost money for the past three years running, largely because of disastrous bets on two companies: Valeant and Herbalife. During that time, his net worth has dropped by more than half, to an estimated $1.1 billion. Recently he’s managed to turn things in the right direction, with his Pershing Square Holdings posting gains of 15.8% through September 30, according to the firm.

“Ackman’s foray into impact investing began in 2011 when Agassi, a tennis champ with eight Grand Slams under his belt, pitched him on his new fund, the Turner-Agassi Charter School Facilities Fund. Agassi, who had teamed up with professional impact investor Bobby Turner, promised Ackman that his capital would go toward the construction of 100 new charter schools for low-income children by 2020 in areas like the Bronx and Southwest Detroit—and that he would see double-digit returns, to boot. Ackman put in $10 million and agreed to take calls from other potential investors who were deciding whether to plunk down their own money. (Ackman, who began playing tennis at age 7, says he managed to beat Agassi in a doubles match—sometime after the two first met in 2011).

“With that, Ackman became a vocal and early proponent of impact investments, which are designed to reap a financial return as well as some positive social or environmental impact. His foundation has put a total of $42 million toward these investments in recent years, in areas ranging from affordable housing to financial inclusion to education…

“His largest impact investment to date is in the Turner-Agassi Charter School Facilities Fund, which has financed construction for 79 new charter schools that have served over 41,000 students since 2011. It generates returns for investors by leasing or selling new schools to charter school operators like KIPP at a profit. Ackman has put a combined $20 million into two funds. (Stewart Rahr, another U.S. billionaire and a Forbes 400 member, has put in $10 million.)..

“Ackman, who signed the Giving Pledge in 2012 and promised to donate more than half his wealth, has pledged or donated over $400 million to organizations like Teach for America and Human Rights Watch through his foundation.”

Someone should tell Mr. A koan that his investments and gifts are undermining a basic democratic institution and harming the teaching profession by sending inexperienced amateurs into classrooms to replace professional teachers. At the same time, he is helping to kill unions.

Maybe that, plus return on investment, is exactly what he wants.