Caledonia Investments (Caledonia) has scooped up a further 1.5 per cent of online broker Etrade Australia, taking its total stake to almost 12 per cent and increasing the pressure on Australia and New Zealand Bank (ANZ) to hike its takeover bid.

Caledonia has spent $6.4 million over the last three weeks buying up a further 1.52 million shares in the company.

One million of those shares came from Etrade Financial in the US, which on Monday sold down 2.3 million shares in Etrade Australia at $4.18 each.

It means that Etrade in the US is no longer a substantial holder in Etrade Australia, reducing its total shareholding to about 4 per cent from about 6 per cent.

"Etrade USA has sent a message loud and clear that they are unwilling to sell the balance of their shares to ANZ at the offer price," one market commentator said. "ANZ is not going to succeed at $4.05. The question is will they increase the offer?"

ANZ spokesman Paul Edwards told InvestorDaily, however, that Etrade USA's actions reflect that they think Etrade Australia is fully valued at $4.18.

"Etrade US . . . has taken an opportunity to realise a price for their shares which is a premium to ANZ's offer.  This suggests to us they think Etrade Australia is fully valued," he said.

Edwards added that Etrade USA's actions also meant it would unlikely now come in as a potential bidder to compete with ANZ.

Caledonia has spent almost $11 million increasing its stake in Etrade Australia by 2.5 per cent since the ANZ bid was first announced in mid February.

As the second biggest shareholder in the online broker,  Caledonia is in a position to scupper ANZ's $4.05 bid for the remaining 66 per cent of the company it does not already own.

ANZ needs a 90 per cent shareholder approval rate for the bid to go through.

Share research and advisory group Invest4Profit's Paul Nojin put the cat among the pigeons last month when he declared the $4.05 offer price was "highway robbery".

He said he would advise his clients, who he claims own up to 10 per cent of Etrade Australia, to sell at no less than $6.00.

Shares in Etrade were trading unchanged at $4.18 when InvestorDaily went to press.

Other substantial shareholders in Etrade Australia include UBS, which has a 5 per cent stake in the business. Caledonia Investments was not available for comment.