SYDNEY (Bloomberg) — Bermuda-based Brookfield Infrastructure Partners LP will buy the 60 percent of Prime Infrastructure Group it doesn't already own in a transaction valued at A$960 million ($855 million). Prime shares surged by the most in a year in Sydney.

Prime shareholders will receive 0.24 Brookfield Infrastructure shares for each security they hold, valuing the Sydney-based company at A$1.6 billion or A$4.60 a share, the companies said in a filing to the Australian stock exchange.

Prime shares soared 21 percent to A$4.35 at the 4 p.m. close in Sydney, the most since August 26, 2009. Brookfield ended 0.4 percent higher at $17.15 on August 20.

"Joining forces with established partners at Brookfield Infrastructure enables us to continue to participate in the returns from our current investments, within a larger, more diversified portfolio of high quality infrastructure assets," David Hamill, chairman of Prime, said in the statement.

Prime yesterday reported full-year profit from continuing operations of A$32 million from a A$252.9 million loss a year ago, and said it will pay a dividend of 7.5 Australian cents a share for the June quarter.

The acquisition by Brookfield will create a global infrastructure company worth more than $2.5 billion, the companies said.

Prime shareholders can choose to receive up to 4,000 Brookfield units in cash, at A$4.55 per Prime share for their entire holding, the companies said.