The exact nature of the so-called ‘unforgiveable sin’ in Mark 3:29 has been a subject of debate for centuries, but maybe one fund executive has put his finger on it.

Speaking at this week’s Hedge 2009 conference in London, Fred Fruitman, managing director of family office Loeb Partners Corporation, referred to an FT article this week showing the Church of England’s pension scheme had a “huge great hole” after putting all its investments into stocks towards the end of the ’90s bull market. Financial blasphemy?

“It’s unforgivable,” he told the conference. ”Defined benefit schemes should take very low risks. They should promise their members modest returns and deliver that. There should be no excuse for under-funded pension plans.”

Fruitman said such funds used to invest in lower-risk assets such as government bonds, but said investment policies changed and they began to go after higher returns.

“Suddenly people were investing in hedge funds, private equity — they’re gambling. There’s a finite amount of returns to squeeze out of financial markets and it’s generally single digits. Everyone thinks they’ve got the magic sauce, and then they add leverage.

“If you just put 60 percent in bonds, 20 percent short-term and a bit in equities… There’s no excuse. You can’t outsmart the system.”