(WT) - Big US fund manager Wellington Management has spent $24 million buying extra shares in struggling wine group Treasury Wine Estates, to lift its stake to 6.79 per cent.

Wellington, which is based in Boston in the US, scooped up the extra shares late last week and early this week, buying tranches worth $10 million, $3.5 million and two lots of about $5 million each.

Treasury, the owner of brands including Penfolds, Wolf Blass, Lindemans, Rosemount, Seppelt and Saltram, announced poor first-half results on February 20 and the appointment of food executive Mike Clarke as chief executive after a six-month search for a new boss.

Wellington told the Australian Securities Exchange on Thursday morning that it had lifted its stake in Treasury from 5.73 per cent to 6.79 per cent.

Treasury shares have made small gains in the past few days and were trading at $4.07 at the close on Wednesday. This compares with below $3.50 early this month just after Treasury revealed a $40 million profit downgrade for 2013-14 because of a poor performance in December in Australia and China.

Treasury's first-half profits in 2013-14 halved to $25.7 million when an $80.5 million tax benefit from a ruling by authorities about de-mergers was excluded. Treasury began life as a stand-alone wine company in May 2011 after splitting off from Foster's Group.