Mama Bear Portfolio (MAMA_BEAR)
Developed by Brian Livingston · Multi-Momentum · Med Risk
The Mama Bear Portfolio was developed by Brian Livingston and published in his 2018 book Muscular Portfolios, which introduced a family of systematic strategies designed to be simple enough for individual investors to implement without professional guidance while delivering risk-adjusted returns competitive with institutional approaches. Mama Bear applies multi-asset momentum rotation across a diversified universe, selecting the three strongest assets each month from a broad menu spanning equities, real estate, commodities, and bonds.
Livingston's research philosophy centers on a concept he calls "muscular" portfolio management — strategies that are stronger than passive indexing (which offers no crash protection) but simpler than quantitative hedge fund approaches (which require specialized infrastructure and monitoring). Mama Bear is the moderate-risk offering in this family, positioned between the more conservative Lazy portfolios that hold static allocations and the more aggressive Papa Bear that applies additional momentum refinements.
The strategy selects from a diverse universe that includes US large caps (SPY), US small caps (IWM), real estate (VNQ), commodities (DBC), gold (GLD), and multiple bond instruments. Each month, all assets are ranked by their trailing twelve-month momentum, and the top three receive equal allocation. There is no explicit defensive mechanism, trend filter, or canary signal — the strategy relies entirely on the diversity of its universe to provide natural protection. When equity markets decline, bonds and gold typically rise in the momentum rankings, naturally rotating the portfolio toward safer assets without any binary switching event.
The absence of a cash position or defensive trigger is a deliberate design choice. Livingston argues that binary defensive mechanisms create behavioral challenges for individual investors — the signal to exit equities often arrives during periods of maximum anxiety, when the psychological difficulty of executing the trade is highest. By instead relying on momentum-driven rotation among a diverse set of assets that includes natural hedges, Mama Bear provides implicit crash protection through portfolio composition rather than through explicit defensive signals.
How It Works
Multi-Asset Momentum Ranking
Each month, all assets in the universe are ranked by their trailing twelve-month total return. This single-period lookback captures the core momentum effect — the empirically documented tendency for assets that have outperformed over the past year to continue outperforming over the near term. The twelve-month window provides a stable, slowly changing ranking that minimizes whipsaw trades while remaining responsive to genuine shifts in asset class leadership.
The diverse universe ensures the ranking always contains assets from fundamentally different economic categories. During equity bull markets, multiple equity segments and real estate tend to dominate the top rankings. During deflationary scares, bonds and gold rise. During inflationary periods, commodities and gold gain momentum. The strategy does not predict which environment will prevail — it holds whatever three assets have been performing best.
Top-Three Equal-Weight Selection
The three highest-ranked assets receive equal allocation at approximately thirty-three percent each. This three-position concentration provides enough diversification to absorb a ranking error in one position while remaining concentrated enough to benefit meaningfully from the momentum signal. The equal weighting ensures no single position dominates the portfolio's risk contribution regardless of its momentum score.
During most market environments, the top three positions span at least two different asset categories — providing natural diversification even within the concentrated selection. A typical risk-on portfolio might hold SPY, IWM, and VNQ (three equity-related positions), while a risk-off portfolio might hold GLD, IEF, and TLT (safe-haven assets). The transition between these states occurs gradually as individual assets enter and exit the top three based on their evolving momentum trajectories.
Implicit Defensive Rotation
Mama Bear has no explicit crash protection mechanism — no moving average filter, no canary signal, no cash alternative. Protection emerges organically from the diversity of the asset universe and the momentum signal's natural response to changing market conditions. When equities decline, their momentum scores deteriorate while bonds and gold — which typically appreciate during equity sell-offs — see their scores improve. Over the course of two to four months, this momentum shift rotates the portfolio from equity-dominated to safe-haven-dominated without any discrete switching event.
This gradual rotation produces smoother transitions than binary strategies but slower responses to sudden market crashes. During the initial phase of a sharp decline, the portfolio remains in its prior equity-heavy allocation until the twelve-month momentum window reflects the new trend — typically requiring two to three months of sustained weakness. This lag is the trade-off for avoiding the whipsaw costs that faster signals generate during volatile but ultimately non-threatening market conditions.
Explore Mama Bear Portfolio (MAMA_BEAR)
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