The stock closed at 3.48 levs, up 18.4% from an opening level of 2.94 levs.

Bulgaria, a member of the European Union, hopes to adopt the euro on Jan. 1, 2023.

Ahead of that, an ECB assessment of six of the country's banks found a capital shortfall at Fibank, Bulgaria's fourth-largest bank, of 262.9 million euros ($291.37 million).

The ECB also found a capital shortfall of 51.8 million euros at a smaller bank, Investbank.

Fibank said on Sunday it planned to offer 40 million new shares at 5 levs per share, adding it would consider the issue a success if as few as 4 million shares were sold at the offer price.

Fibank, which has already secured 130 million euros in additional capital, said it had also privately placed a 30 million-euro bond and offloaded bad loans with a nominal value of about 538 million levs.

It said its overall capital adequacy ratio stood at 17.65% at the end of September. Its CET1 capital ratio was 14.79%, above regulatory requirements.

Bulgarian businessmen Tseko Minev and Ivaylo Mutafchiev each own 42.5% of the lender, which had total assets of 9.6 billion levs at the end of September. The remaining 15% has been floated on the Bulgarian Stock Exchange.

($1 = 1.7639 leva)

($1 = 0.9023 euros)

(Reporting by Angel Krasimirov; Editing by Kirsten Donovan)