* Investors sell 31 mln shares at 5 pct discount to Monday's close
* Price reflects good demand for the shares - analyst
* Canada's OTTP says remains as investor with long-term outlook (Adds background, analyst comment, amends slug)
COPENHAGEN, Sept 9 (Reuters) - The main shareholders in Denmark's ISS have sold 16.7 percent of the company's existing shares for $885 million, the catering and cleaning company said on Tuesday.
The shareholders, private equity firm EQT, funds managed by Goldman Sachs, and Ontario Teachers' Pension Plan (OTTP)had planned to sell 23 million shares in a bookbuilding process, but increased the amount to 31 million shares due to strong investor demand.
At a price of 165 Danish crowns per share, the shares in the placement were sold at a 4.9 percent discount to Monday's closing price of 173.50 crowns per share.
"There was good demand for the shares," spokesman for EQT and the funds managed by Goldman Sachs, Morten Hummelmose, told Reuters.
He would not comment on the yield of the investment in for the private equity funds.
EQT and the funds managed by Goldman Sachs delisted ISS after they bought the business for 22 billion Danish crowns ($3.8 billion) in 2005. After Tuesday's placement EQT and Goldman Sachs own 32.7 percent combined.
"The discount is reasonable and the price reflects that there has been a good demand for the shares," Sydbank analyst Soren Lontoft Hansen said.
ISS, one of the world's biggest private employers with more than 530,000 workers around the world, was listed in March at a price of 160 crowns per share. The share price peaked at 203 crowns in May. At 0928 GMT ISS' shares traded at 166.20 crowns per share, down 4.2 percent. (1 US dollar = 5.7835 Danish crown) (1 US dollar = 0.7766 euro) (Reporting by Teis Jensen; editing by Sabina Zawadzki and Louise Heavens)