The Australian Council of Superannuation Investors (ACSI) has fired a broadside at underwriting fees charged by investment advisers and banks for rights issues, arguing companies are often paying more than twice as much as they should to mitigate risks.

In a report to be released on Monday, ACSI found a mismatch between fees and underlying risks assumed. It said local companies have paid underwriters a premium of more than $170 million above the “theoretical value" of risk taken by advisers. The report examined 63 underwritten rights issues conducted by ASX300 companies between 2010 and 2012.