Key members of the public bodies that regulate and fund charter schools in Washington D.C. have taken part in official decisions that stood to benefit themselves, their colleagues, employers and companies with whom they have business ties, according to a Washington Post investigation.

The Post's review found conflicts of interest involving almost $200 million worth of business deals, at more than a third of the city's 60 charter schools.

Several of those deals involve Thomas A. Nida, who chairs the D.C. Public Charter School Board and is also a senior vice president at United Bank. Nida has taken part in official decisions involving schools, their landlords or developers who are also doing business with his bank. Nida voted, for example, to increase enrollment at schools, which resulted in the schools receiving more public funding, and effectively helping them repay loans to his employer, United Bank. Nida said his business ties did not influence his votes.

The Post's two day series also detailed how the charter schools had surpassed the traditional public schools in the academic achievement of disadvantaged students, who make up two-thirds of public school enrollment in the District. The ability of the schools to tap into private donors, bankers and developers has made it possible to fund impressive facilities with more programs and smaller class sizes.

In many cases, those programs and facilities have drawn students, which brings more public funding to the schools. Enrollment at the traditional public schools has fallen 42 percent since Congress created the charter system a dozen years ago, and the growth in charter schools accounts for almost all of that decline.