Sipef called time on the rally in palm oil prices, but signalled some optimism over a recovery in rubber values – even as Tokyo futures in the tyre ingredient hit a four-month low.
Baron Bracht, in his swansong as the plantations group's chairman, said that palm oil prices - having jumped by 45% since August in Rotterdam to top $700 a tonne – may struggle for further headway, given the prospect of higher supplies of rival vegetable soyoil.
"Despite these substantially better [palm oil] prices in the last two months, there are no indications that this rising price trend will continue in the second half of the year," Baron Bracht told shareholders.
"Adequate palm oil stocks, and the altered export tax regimes in Argentina, which encourage the planting of soybeans, lead us to expect palm oil prices to stagnate at current levels throughout the rest of the year."
The farm sector in Argentina, the top soyoil exporter, has received a boost from the government of Mauricio Macri since he became president in December, with the new administration cutting export taxes and quotas on crops, and allowing a depreciation of the peso which has boosted trade competitiveness.
The comments came ahead of data on Friday from the Malaysian Palm Oil Board which are expected to show Malaysia's palm oil inventories falling 8.8% last month, from May, to 1.64m tonnes – the weakest figure since March 2011.
Malaysian palm exports are seen has having surged 13.1% month on month to 1.32m tonnes, outpacing a 3.9% rise to 1.35m tonnes in production.
However, palm output is seen as heading for a stronger recovery ahead, as the hangover wears off from depressed rainfall levels in South East Asia, dryness blamed on the El Nino weather pattern.
Baron Bracht said that Sipef itself had "clearly felt the delayed effect of the El Niño drought on the mature plantations of North Sumatra, with lower production volumes set to persist in June.
"However, we are seeing stronger fruit bunch formation that should guarantee higher volumes from the second half of the year."
The plantations group has sold forward 51% of its forecast palm oil production for the year, a proportion in line with the extent of hedging a year ago.
However, its sales in rubber, at 66% of output, were a little behind the pace of 2015, amid some optimism in the company over price rises.
"Rubber prices on the world market are recovering," Baron Bracht said.
"As rubber stocks in the biggest Asian consumer countries gradually shrink, we are seeing a fresh upturn in demand, allowing us to gradually move away from the exceptionally low price levels of the last 18 months."
"We will gradually continue to sell in this slightly increasing market."
Nonetheless, he acknowledged the threat to prices from China, the top rubber importer, flagging that "the short-term markets remain strongly dependent on China's purchasing behaviour".
The comments follow Chinese customs data on Wednesday showing the country's imports of rubber eased to some 470,000 tonnes last month – a drop of 6% from April.
The data were, with a strengthening yen, seen as fuelling a drop in rubber futures in Tokyo to below 150 yen a kilogramme in the afternoon session, for the first time since February.
Shanghai rubber futures closed on Wednesday, the latest session, at 10,450 renminbi per tonne, down 1.6% on the day, although above a four-month low of 10,145 renminbi per tonne set last week.
On the Brussels stockmarket, Sipef stock stood 0.4% lower at E49.305 in lunchtime deals.
*In the Kuala Lumpur palm oil market, benchmark futures closed at 2,582 ringgit a tonne, down 0.1% on the day, and down some 7% from a March high.
However, futures remain up some 4% for 2016.
By Mike Verdin