The present invention relates to an iterative method and an apparatus for distribution-independent detection of intermediate outliers and outliers in the distribution tail of streamed data. A considerable sequence of streamed data is sequentially read and subsequently assigned to matching bins. The bins are adaptively allocated when, where and if they are needed. Each bin range expands concurrently with the distribution range of the accumulating items assigned to the bin, adding a margin. For every N'th read item, overlapping or adjoining bins are merged, whereupon the bins are assessed for insider preclusion. Information regarding outliers is extracted from the remaining outlier bins when the entire data sequence has been processed.