The Ontario government plans to sell more than 81 million shares at a price of $19 to $21 a share in its public offering of Hydro One later this year.

The first release of shares, for about 15 per cent of the company, would raise about $1.7 billion.

A new prospectus was filed today for the electricity generation and transmission company, which is to be listed only in Toronto and not in U.S. markets.  

The share price range listed in the prospectus is "temporary" and only provided in order to attract potential investors, Energy Minister Bob Chiarelli said.

"The final share price will be determined after a defined marketing period, as well as further analysis," he said.

About 25 per cent of Hydro One shares would be reserved for retail investors, with the rest reserved for institutional investors.

Hydro One Inc. has approximately $23 billion in assets and had 2014 revenues of over $6 billion.

The province has said it plans to sell up to 60 per cent of Hydro One, the giant transmission utility and raise up to $9 billion, of which $5 billion will go to pay down Hydro One debt. The other $4 billion is to help pay for the government's 10-year public transit and infrastructure plan, which has a price tag of $130 billion.

"Unlocking the value of our provincial assets will provide billions towards the single largest investment in transit and transportation infrastructure in the province's history," Chiarelli said.

The opposition parties and several municipalities across the province oppose the sale, arguing that the move will only drive up electricity prices. The government counters that it will remain the single largest shareholder in Hydro One.

After the initial offering, three more of similar size are expected.

The listing date is expected to be in November.