Time-series momentum and relative ranking
Moskowitz, Ooi, and Pedersen distinguish own-return momentum from momentum based on relative performance. Their research does not validate this page's shorter, long-only example. A momentum oscillator is a measurement; a strategy must also specify when to act, how much to hold, and when to exit.
- If asset A returns -2%, B -5%, and C -9%, A ranks first. The zero-threshold time-series rule holds none of them. These invented returns demonstrate why the two methods cannot be substituted.
- Relative strength here means performance ranking, not the RSI oscillator. A single chart strategy does not establish the performance of a ranked portfolio.
| Decision | Time-series momentum | Cross-sectional momentum |
|---|---|---|
| Comparison | Current price versus this asset's earlier price. | Returns across a predefined universe at the same decision time. |
| Example signal | Hold long when its 63-bar return exceeds zero. | Buy the highest-ranked assets; a long-short version also sells the lowest-ranked assets. |
| All assets falling | A long-or-cash rule can hold cash. | The highest-ranked asset can still be a loser in absolute terms. |
| Required data | One price history and its adjustment settings. | Synchronized histories, historical membership, delisted assets, weights, and a rebalance calendar. |