(Adds details, analyst comment) MOSCOW, April 12 (Reuters) - The share of foreign investors among holders of Russia’s OFZ treasury bonds slumped further in March to its lowest since August 2015, the central bank data showed on Monday. Foreign investors’ share of Russian debt has been on decline for months and its slide accelerated recently amid intensified fears of fresh U.S. sanctions against Moscow. Non-residents accounted for 20.2% of OFZ bondholders as of end-March compared with 22.7% as of March 1, the data showed. In late March a year ago, foreigners owned around 32% of OFZ bonds that Russia issues to plug holes in the budget. “The largest exodus (of foreign investors) from the Russian market was observed on particular days with increased volatility due to geopolitical risks,” the central bank said in a report on financial markets. OFZ bonds, which used to be popular among foreign investors thanks to lucrative yields, took a hit after U.S. President Joe Biden said in March his Russian counterpart, Vladimir Putin, would “pay a price” for efforts to meddle in the 2020 U.S. presidential election, allegations that Moscow denies. Yields on 10-year OFZ bonds, which move inversely to their prices, jumped to a one-year high of 7.36% in the second half of March from around 6.7% seen in late February. The latest wave of non-residents exiting OFZs took place in late March, which had an immediate negative impact on the rouble, BCS brokerage said. After Russia said it had started a planned combat readiness inspection of its army and NATO expressed concerns about a Russian military build-up near eastern Ukraine, the already weak rouble hit a five-month low against the dollar in early April. “In the current environment, forecasting future rouble trend is now almost exclusively the job of political scientists and military experts, not economists,” BCS said. (Reporting by Andrey Ostroukh and Elena Fabrichnaya; Editing by Alison Williams and Bernadette Baum)