"They sold quickly in late December after nearly ending their harvest, then the trade has been slow in the past two weeks," said a trader with a foreign firm in Ho Chi Minh City.
The four-month harvest ended this month in the five provinces in Vietnam's Central Highlands coffee belt. A state trader based in the key growing province of Daklak said he could not buy many beans from domestic markets.
"Farmers reckoned a dryness now would have an impact on the crop in the next few months, so they are not selling to prepare for a price rise or at least to have coffee in stock," he said.
Farmers are watering coffee trees for the next crop cycle with the new harvest starting in October. But another foreign trader told Reuters many outright contracts for spot shipment have been signed in recent days.
"Exporters are not willing to offer discounts to futures contracts as they are afraid of risk after the festival, so they only sell for immediate shipment," he said, adding that deals were signed at $645 to $655 a tonne, basis FOB.
Vietnamese robusta grade 2, 5 percent black and broken are put this week at $650 to $670 a tonne, from $630 to $650 a week ago, after buying by speculators and funds in London pushed May contract to close $11 higher at $792 a tonne on Monday.
Local prices in Daklak also firmed to 9,870 dong (62.6 cent) per kg on Tuesday, from 9,720 dong on Monday and a range of 9,470 dong to 9,600 dong last week.
The state trader said farmers would sell much more if prices were above 10,000 dong per kg.