Clean energy firm Hanergy Mobile Energy, which owns a majority of Hong Kong-listed Hanergy Thin Film, said it plans to take it private for not less than HK$5 per share via a cash acquisition or share replacement and then relist it on China's A-share market.

At that price, Hanergy Thin Film would be valued at HK$210.73 billion ($26.88 billion), higher than the HK$164.8 billion the solar panel equipment making company was worth when it stopped trading on May 20, 2015 at HK$3.91.

Hanergy Thin Film, under a high-profile investigation by Hong Kong's Securities and Futures Commission (SFC), is yet to get approval to resume trading in Hong Kong.

"As Hanergy Thin Film Power Group has been suspended from trading for over three years, in order to protect the interest of small and medium investors ... we decided to issue a buyout offer to all the investors of the listed company," Hanergy Mobile Energy said in a statement posted on its website on Tuesday.

The parent company said in a separate statement to the media that the relisting plan shows its confidence in China's A-share market after China recently said it would support offshore companies listing onshore.

Reuters reported last week a decision from Hong Kong regulators on the future of Hanergy Thin Film could come within weeks after a hearing last month.

Hanergy Thin Film's stock collapsed spectacularly in May 2015, when, after a five-fold increase over the previous 12 months, it plunged 47 percent in 24 minutes. The crash wiped out $19 billion in market value before the company asked for the trading to be suspended.

Hanergy Mobile Energy sent the take-private proposal to the Hong Kong unit on Oct 12 and held a board meeting to approve the proposal on Oct 18, the statements on Tuesday said.

According to previous filings, the SFC was concerned that the parent was heavily indebted to the unit, which received a bulk of its revenue through transactions with the parent.

(Reporting by Clare Jim; Editing by Sayantani Ghosh and Muralikumar Anantharaman)

By Clare Jim