NEW YORK (Reuters) -JPMorgan is reviewing the impact that newly imposed U.S. sanctions on Russian sovereign debt may have on its emerging market bond indexes, a source familiar with the matter said.

The U.S. government broadened restrictions on trading of Russian government debt on Tuesday in a bid to punish Moscow for ratcheting up its conflict with Ukraine.

JPMorgan is a major provider of emerging market indexes for local currency and hard currency bonds.

The indexes are key performance benchmarks for international investors in emerging market debt, so membership can help a country sell bonds and reduce its borrowing costs.

The U.S. Treasury said on Tuesday it was prohibiting participation in the secondary market for Russian government bonds that will be issued after March 1, in a move aimed at curbing Russia’s ability to access external funding.

U.S. investors have been banned from buying new dollar-denominated Russian debt since 2014, when Russia annexed Crimea.

U.S. banks have been barred from taking part in the primary market for non-rouble sovereign bonds since 2019 and last year U.S. President Joe Biden also barred U.S. financial institutions from taking part in the primary market for rouble-denominated Russian sovereign bonds.

JPMorgan’s emerging market strategists said in a note to clients on Wednesday that the new U.S. sanctions on Russian sovereign debt were likely to have limited implications for the international investors that already hold Russian paper.

With total foreign ownership of Russian debt at about $64 billion, and Russia’s reserves in excess of $630 billion, sanctions on sovereign debt are likely to have a limited economic impact, said Elina Ribakova, deputy chief economist at the Institute of International Finance.

(Reporting by Davide Barbuscia in New YorkEditing by Chris Reese and Matthew Lewis)