By 1924, it had foreign branches in Trieste and Gorizia,[2]: 108  and domestic ones in Brežice, Celje, Črnomelj, Kranj, Maribor, Metković, Novi Sad, Ptuj, Sarajevo, and Split.

[2] On its core Slovenian market, it was briefly eclipsed by Slavenska Banka but regained a dominant position following that bank's bankruptcy in 1925, ahead of local rivals the Credit Institute for Commerce and Industry (Slovene: Kreditni zavod za trgovino in industrijo, the former local branch of Austria's Creditanstalt converted into a fully-fledged local bank in 1920[3]: 10 ) and the Cooperative Business Bank (Slovene: Zadružna gospodarska banka).

[4]: 190  In 1927, it merged with Trgovska banka, thus forming the largest bank in Slovenia and the fourth-largest in all of Yugoslavia.

[1] Like most other domestic commercial banks in Yugoslavia, LKB was heavily impacted by the European banking crisis of 1931 and had to adopt a voluntary program placing a moratorium on its liabilities in the spring of 1932, from which it partly emerged through a restructuring in 1935 in which only small depositors were repaid in full.

[6]: 747 In 1920, the bank started construction of a new head office building designed by Czech architect František Krásný [cs] with sculptures by Franc Berneker, prominently located on Slovenska Cesta [sl] (then named Tyrševa Cesta).