Under Hertzka, UE signed contracts with a number of important contemporary composers, including Béla Bartók and Frederick Delius in 1908; Gustav Mahler, Arnold Schoenberg and Franz Schreker in 1909.

Anton Webern and Alexander von Zemlinsky were signed in 1910, Karol Szymanowski in 1912, Leoš Janáček in 1917 and Kurt Weill in 1924.

The firm's avant garde directions continued after World War II, when UE published works by a number of significant composers, among these Luciano Berio, Pierre Boulez, Morton Feldman, Mauricio Kagel, György Kurtág, György Ligeti and Karlheinz Stockhausen.

The Internet Law professor Michael Geist wrote a column for the BBC, suggesting UE's actions lacked reasonable legal ground.

[3] The International Music Score Library maintained that UE's actions lacked legal justification, and reopened on 30 June 2008.