Surprised? You shouldn't be. When profits were rolling in, they spent and investors didn’t bother to look at the details. Now that funds are under-performing, spending patterns are viewed more closely.

Investors are starting to sour on the idea of reimbursing hedge funds for multi-million dollar trader bonuses, lavish marketing dinners and trophy office space.

Powerful firms such as Citadel and Millennium Management charge clients for such costs through so-called "pass-through" fees, which can include everything from a new hire's deferred compensation to travel to high-end technology. In the end, investors pay more than double the industry's standard fees of 2% of assets and 20% of investment gains, which many already consider too high.

Investors have for years tolerated pass-through charges because of high net returns, but weak performance lately is testing their patience.

• Clients of losing funds last year – e.g., those managed by Blackstone Group’s Senfina Advisors, Folger Hill Asset Management, and Balyasny Asset Management, likely still paid fees far higher than 2% of assets.

• Clients of shops that made money – e.g., Paloma Partners and Hutchin Hill Capital, were left with returns of less than 5% partly because of a draining combination of pass-through and performance fees.

• Millennium, the $34Bn firm led by Israel Englander, charged clients its usual fees of 5 or 6% of assets and 20% of gains in 2016, leaving investors in Millennium's flagship fund with a net return of just 3.3%.

• Citadel, the $26Bn firm led by Kenneth Griffin, charged pass-through fees that added up to about 5.3% in 2015 and 6.3% in 2014. While those expenses for 2016 are not yet available, Citadel's flagship fund returned 5% percent in 2016, far below its 19.5% annual average since 1990.

Defenders of pass-throughs said ……   the fees were necessary to keep elite talent and provide traders with top technology. They said that firm executives were often among the largest investors in their funds and pay the same fees as clients.

Understood, but frustration is starting to show.