Gabon’s international bonds sank the most on record and shares of foreign companies with operations in the country tumbled as a military coup spooked investors in its oil sector and its debt linked to conservation projects.

Dollar bonds due 2025 and 2031 posted the biggest declines among emerging-market peers, with some analysts predicting the selloff may spill over to other African countries with high political risk. European stock markets joined the selloff, with mining group Eramet SA, oil-and-gas producer Maurel & Prom and a listed unit of TotalEnergies SE falling amid increased trading volumes.

The seizure of power, the ninth in Africa in the past three years, highlights the uncertainty of investing in frontier nations at a challenging time for the global economy when elevated inflation is spurring voter dissatisfaction and boosting political risk. It undermines not only the outlook for Gabon’s bonds, but could also have spillover effects of the debt securities of neighboring countries, including Cameroon, said Mark Bohlund, senior credit research analyst at REDD Intelligence.

“Central Africa does not have the same recent history of military coups as West Africa but I still think there will be concern of contagion,” he said. “In Cameroon and Republic of Congo in particular, there is a similar discontent with the long-time rule and the prospects of a dynastic transitions.”

Gabon’s dollar bonds due June 2025 slid 8.6 cents on the dollar to 84.66 for the worst performance on the Bloomberg Emerging Markets Sovereign Index. Cameroon’s November 2025 dollar notes were down 0.4 cents on the dollar, the most in a day since July, to 97.59 cents. International bonds of Ethiopia, Ivory Coast, Senegal and Ghana also dropped, joining the ranks of the 20 worst performers in the gauge.

Gabon’s bond losses will concern investors who had taken part in the country’s recent debt-for-nature swap, an increasingly popular means of fund-raising for countries committing to environmental protection. The $500 million deal helped the country reduce its debt and lock in funds for marine conservation.

“The debt for nature swap has been completed and will thus not be affected directly,” Bohlund said. “But the price of the bond issued by the Gabon blue bond master trust is likely to fall to a lesser extent than the unguaranteed Eurobonds.”

Eramet, which produces manganese in Gabon, tumbled 14% with trading volumes at about 15 times the 30-day average for this time of day. A company spokesman said the group had stopped mining and train-transport operations out of precaution.

Shares of Maurel & Prom, which two weeks ago announced a $730 million deal to buy Gabonese firm Assala Energy, plunged 18%. The company remains confident in the outcome of the deal and its production in the country is unaffected, it said in a statement to Bloomberg.

TotalEnergies, which has been a key player in the country for decades, saw its listed unit TotalEnergies EP Gabon drop 11%. Norway’s Panoro Energy, which produces oil in Gabon, fell 2.5%.