Shares in Australia's surfwear retailer Billabong International plunged more than 48 percent on Monday after the company completed the institutional component of its accelerated pro-rata renounceable entitlement offer.

At 1125 local time, Billabong shares fell 89.5 AU cents, or 48. 9 percent, to 93.5 AU cents.

On Thursday, the company announced a capital raising of 225 million AU dollars ($225.56 million) to pay down its debt and lowered its full year profit guidance.

Billabong on Monday said it had completed the institutional entitlement offer.

It said eligible institutional shareholders took up more than 79 percent of new shares available to them, raising 155 million AU dollars ($155.39 million).

Trading in new shares on the Australian Securities Exchange is expected to commence on June 29, the company said.

Billabong Chief Executive Laura Inman said it was pleasing to see such strong institutional support for the offer.

"Billabong has had its challenges in recent times but milestones such as today ensure we have the opportunity to reinvigorate the business and, over time, create further value for our shareholders through our transformation agenda," she said in a statement on Monday.