Young’s partner in accounting Crossword Clue

 The answer to the crossword clue "Young's partner in accounting" is ERNST. It is a 5-letter word.

The clue is a bit of a pun, as "Young" is also a surname. The accounting firm Ernst & Young was founded in 1885 by Arthur Young and Alfred Ernst. The firm is one of the Big Four accounting firms in the world.

I hope this helps!