This contribution focuses on the use of the multifunctional German word form es in the learner corpora MERLIN and DISKO (1,452 texts; 3,700 manually annotated occurrences of es). These corpora cover a wide proficiency range (A1-C1), and they include an L1 control group. Due to its multiple functions, using es is assumed to be challenging for learners. After laying out its main functional features, this paper first addresses the question of whether the frequency patterns of es actually differ between L1 und L2 texts, which is shown to be true only for beginning learners, and whether differences related to learners’ L1 can be observed, which seems to be the case. Secondly, the study links the emerging use of different es types and their relative frequencies to CEFR proficiency levels. A third focus regards the accuracy of es usage, which is generally high but differs among the various es functions, with anaphoric es presenting the greatest challenge for learners. A closer look at interlanguage structures reveals that learners often omit compulsory es and that they use redundant es in peculiar syntactic slots. Furthermore, the use of anaphoric es without clear textual reference regularly encumbers the reading process of the texts.