If the assets and their allocation in an index are the same (same assets with the same weights) in a portfolio, then: The portfolio will outperform the index The performance of the portfolio and the index will be the same in all periods. This will also result in almost 0 tracking error. The performance of the portfolio may be higher than the index in some periods, and lower in other periods. Over a long term the portfolio will perform the same as the index but with tracking error. portfolio performance is unrelated to index performance The portfolio will underperform the index