The non-profit that took on Valeant has a new investigation on another hedge fund darling

A new investigation out Monday casts doubts on Canadian National Railway, a popular holding for money managers.

The Southern Investigative Reporting Project's Roddy Boyd published an investigation of the railway company. Here is SIRF on its findings:

• "For over 15 years Canadian National earned hundreds of millions of dollars in profit by marking up rail construction costs up more than 900 percent to a public-sector client."
• "Canadian National regularly engaged in questionable business practices like charging internal capital maintenance and expansion projects to the same taxpayer-funded client and billing millions of dollars for work that was never done."
• "A just-released auditor general investigation suggested a series of reforms that will reduce these profits."
• "For years, train yard personnel, under intense pressure from management, have intentionally misreported on-time performance, helping it boost revenues by hundreds of millions of dollars."

The stock was down about 2% in the hours after the report was published. Hedge funds that have held the stock include Point72 Asset Management, D.E. Shaw, Citadel, Two Sigma, AQR and Renaissance Technologies, according to regulatory filings analyzed by Bloomberg. Pensions like CalPERS have also been investors.

SIRF is a journalism non-profit focused on financial investigations and runs on donations. The group previously broke news on embattled pharmaceutical company Valeant's relationship with Philidor.

You can read the full SIRF report on Canadian National Railway here.