* OHL to raise 1 bln euros in share issue
* Shares offered at 62 pct discount to Tuesday's close
* Top shareholder poised to sell 9.54 pct stake before issue (Recasts with details from prospectus)
By Carlos Ruano and Paul Day
MADRID, Oct 7 (Reuters) - Spanish builder and toll-road operator OHL on Wednesday said its main shareholder would likely sell down its stake ahead of a planned 1 billion euro ($1.12 billion) share issue that will be carried out at a highly-discounted price.
The company, whose debt has mounted after an economic crisis at home, said it would issue shares at 5.02 euros each, a 62 percent discount from their closing price on Tuesday. The price was lower than analysts were expecting.
The chairman of the group, octogenarian billionaire industrialist Juan Miguel Villar Mir, had said in September that new shares would be issued at around or slightly below their then market price of 12 euros per share.
In the share prospectus published on Thursday, OHL said its main shareholder, Inmobiliaria Espacio -- the holding company used by Villar Mir -- was "considering" a 9.54 percent sale of OHL shares before the issue.
But in the Spanish version of the prospectus OHL said it had "requested" banks to organise the sale.
The sale would still leave the main shareholder with a 50.01 percent controlling stake, which Villar Mir has said he would maintain after the issue.
OHL shares closed down 0.7 percent at 13.050 euros, still above the 7.73 euro theoretical ex-rights price (TERP), or the market price a stock theoretically has after a new rights issue.
The company will use 632 million euros to pay down debt and 340 million euros to fund construction projects, it said on Wednesday. It confirmed major shareholder Grupo Villar Mir would keep a majority stake after the issue.
The new shares will start trading from Oct. 30.
OHL, which has aggressively borrowed against assets to fund investments, had net debt of 5.7 billion euros at end-June, giving it a net debt to earnings ratio - a measure of a company's ability to decrease its debt - of around 5.
Analysts expect the funds from the share issue to reduce this ratio to around 4.
OHL also said on Thursday it would buy back 300 million euros worth of bonds from 3 different bond issues worth around 1 billion euros in total.
The share issue will be underwritten by Bank of America Merrill Lynch, Deutsche Bank, JPMorgan Securities, Societe Generale, UBS, Banco Santander and Credit Agricole.
The company has also said it plans to sell engineering and construction assets in the fourth quarter to reduce debt. ($1 = 0.8891 euros) (Additional reporting by Liz O'Leary, Andres Gonzalez and Sonya Dowsett; Editing by Julien Toyer and David Evans)