AGL Energy has raised $356.1 million through the institutional stage of its $900 capital raising to help pay for the Loy Yang brown coal power station.

The offer to retail shareholders is open until June 19 and aims to raise $543 million.

AGL emerged as the nation’s equal largest electricity company – by capacity – last month after its $448 million takeover of Australia’s third largest coal fired power station was approved.

It is seeking to raise $1.55 billion to help pay Victoria’s Loy Yang’s sizeable $2.5 billion debt and raised $650 million via a subordinated note issue earlier this year.

AGL shares are being issued at a one-for-six ratio at $11.60, a discount of about 20 per cent to its retail investors.

AGL shares had fallen 3.5 cents to $15.075 by 1255 AEST but are up more than four per cent since the Loy Yang approval several weeks ago.