Hmmm, I don't think that QModelIndex instances can be "shared" among models - an index into a model is specific to that model, and can't be used to refer to an item at the same location in a different model, if that's what you mean you are trying to do. You can extract the row and column numbers from the index and use them to retrieve the corresponding index from the other model, but then you still need to check that both the source and target indexes are valid.