The falling oil price has caught-out investors in a retail bond linked to a leading North Sea producer.
EnQuest issued the bond two years ago, offering an attractive 5.5% interest rate until 2022.
The company used it to raise £155million to help develop the Kraken field off the Shetland Islands.
However, the price of the bond has tumbled in recent weeks, down from 105p in March to 68.78p last week.
EnQuest insisted that all the risks were fully explained to investors.
Shares in the company have also been hit hard by the oil price decline, closing on Friday at 49.57p, compared to almost 150p in March.
One oil analyst said the future of the company was not in doubt.
“They are not an exploration company — they have solid production and are hedged at high prices. They will be fine,” he said.
A spokesman for the company said: “EnQuest seeks to deliver sustainable long-term growth through a focus on oil field production and development, targeting opportunities in maturing basins that are not material enough for the large oil companies.”