April 4 (Reuters) - International Paper ( IP ) said on

Thursday it would seek a secondary London listing if it buys

British paper and packaging peer DS Smith ( DITHF ) and the

combination could deliver at least $514 million of pre-tax cost

savings on an annual basis.

International Paper ( IP ) last month stirred up a potential

bidding war over DS Smith ( DITHF ), making a takeover proposal that

valued the UK firm at 5.72 billion pounds ($7.24 billion), or

415 pence per share.

The U.S.-listed paper company has yet to make a firm offer

for DS Smith ( DITHF ). It, along with rival suitor Mondi ( MNODF ), have

until April 23 to make a firm offer or walk away.

International Paper ( IP ) said "significant progress has been

made" in due diligence, as it lays out detail on the possible

combination, including a proposal to establish a European

headquarters in London and a secondary share listing on the

London stock exchange.

Shares in DS Smith ( DITHF ) were up 1.3% by 1121 GMT, and hit their

highest level since October 2021 at 408.2 pence.

International Paper ( IP ) shares were down 1.2% premarket.

DS Smith ( DITHF ) had reached an in-principle agreement with its

UK-listed rival Mondi ( MNODF ), which made an all-share takeover

proposal valuing DS Smith ( DITHF ) at 5.14 billion pounds.

($1 = 0.7901 pounds)