Iron ore miner Atlas Iron Ltd has amassed a controlling stake in iron ore explorer Giralia Resources NL.
Atlas on Wednesday had a stake in the target of 51.96 per cent, up from 49.89 per cent previously.
The friendly, off-market offer was recommended by Giralia's board on December 21 when it was unveiled and is scheduled to close on February 28.
Atlas has offered Giralia shareholders either 1.5 Atlas shares per Giralia share or 1.33 Atlas shares plus 50 cents cash for each Giralia share.
When it was announced, the bid valued Giralia at $828 million, but Atlas' shares have recently gained ground, so the offer has increased in value to more than $1 billion.
The bid is conditional on a minimum acceptance level of 90 per cent.
Atlas says a takeover of Giralia will expand its Pilbara landholdings by about 50 per cent.
Shares in Atlas closed four cents lower at $3.75 while Giralia shares eased four cents to $5.54.
ASX Stock Chart for AGO ASX Stock Chart for GIR
AGO Price at posting:
$3.75 Sentiment: Buy Disclosure: Held