Russell Rebalancing

Every year, FTSE Russell rebuilds the membership of its US indices (Russell 1000, 2000, 3000) from scratch — a process called reconstitution. Companies are re-ranked by market capitalization, and additions/deletions are announced in June and made effective at the close on the last Friday of June (the "rebalance date").

Because trillions of dollars track the Russell benchmarks passively, index funds and ETFs must trade the additions and deletions in size, price-insensitively, to stay aligned with the new membership. That demand/supply shock is heaviest in the small-cap, less-liquid Russell 2000, and it has historically been followed by a short relief bounce into early July.

This strategy monetizes that bounce with a single, fully mechanical trade per year:

• Buy IWM at the close of the first trading session after June 23.
• Sell at the close of the first trading session of July.
• Hold cash the rest of the year.

It is a market-timing strategy: entry and exit are fixed trading dates, not price levels. It recommends no individual stocks and defines no stop or target — its only risk control is the very short, fixed holding period (about five trading sessions) and being flat otherwise.

Best for

• Normal years with heavy passive participation and no competing macro shock, when reconstitution flow is the dominant driver of small-cap prices around month-end.
• Years where pre-positioning around the rebalance unwinds into a clean early-July bounce.

Avoid when

• A macro event (rate decisions, risk-off shocks, thin-liquidity holiday distortions) swamps the flow.
• The effect is arbitraged away — it is well known and has decayed over time.
• Small caps are in a strong independent trend that overwhelms the seasonal signal.

Market behaviour exploited

Mechanical, price-insensitive index-tracking flow forced by reconstitution — a structural microstructure effect, not a fundamental or news-driven one.

The edge is a tendency, not a guarantee, and it has weakened as it became widely documented.

The rules live in one pure, date-driven core (russellRebalancingSignalFromBars) that backs both the live strategy state and the backtest adapter, so they can never drift.

Entry

The first trading session strictly after June 23.

Implementation: at the latest bar, entry fires when the session crossed the June-23 boundary since the previous session — i.e. the previous bar's date is on/before June 23 and the current bar's date is after it, in the same calendar year. Because it keys off actual bar dates, it lands on the correct open session regardless of weekends/holidays (usually June 24; June 26 when June 24–25 is a weekend) and fires exactly once per year.

Exit

The first trading session of July.

Implementation: exit fires when the current bar is in July and the previous bar is still in June (same year) — the first July session. It fires once (later July sessions have a July predecessor). Entry and exit are mutually exclusive on any single bar.

Position management

• One trade per year; flat (in cash) otherwise.
• No stop-loss, no profit target — the exit is a fixed date. entryPrice/stopLoss/firstTarget/riskPercent/rewardRiskRatio are reported as null (never invented).
• Holding period: 5 trading sessions in every backtested year.

Deterministic, identical in construction to Santa Claus Rally and Turn of the Month — it uses the shared seasonalConfidence model. confidenceScore is a setup-quality measure (0–100), not a probability of profit.

• Inside the window → 100 (Exceptional).
• Approaching (≤10 days) → 60-less, rising with proximity (e.g. 5 days out → 20).
• Far / finished → 0.

Bands (library-wide): <70 Weak · 70–79 Good · 80–89 Strong · 90–100 Exceptional.

The API returns ["Russell reconstitution window is active"] while the window is Active, else []. Operationally:

• It is on/after the first trading session past June 23.
• Position entered at that session's close in IWM.
• No stop or target set — the exit is the date, not a price.
• Exit at the close of the first July session.
• Flat (in cash) outside the window.
• Treat the historical edge as a tendency, not a guarantee — size accordingly.

• Structural, not predictive. The edge comes from forced, mechanical index flow, not from forecasting news or fundamentals.
• Objective and fully mechanical. Entry/exit are unambiguous calendar rules — no discretion, no indicator tuning.
• Minimal market exposure. In the market ~5 sessions per year; in cash ~98% of the time, so tail risk is tightly bounded.
• Documented, positive-expectancy backtest. 70% win rate, 3.8 profit factor, +1.46% average over 27 real years, shallow 4.5% max drawdown.
• Non-correlated. A one-week small-cap seasonal sits apart from trend/mean-reversion books.

• Small, decaying edge. ~1.5% per trade; well known and arbitraged, so future returns may compress.
• Small sample. One trade/year → 27 observations. Statistically thin; a few years dominate.
• Macro override risk. 2010 (−4.5%) and 2008 (−2.3%) show a risk-off tape can swamp the flow.
• No adaptive risk control. A fixed-date exit means no stop; a bad week is taken in full (bounded only by the short hold).
• Single-asset, single-window. No diversification within the strategy; execution slippage in IWM around a high-volume rebalance close is a real cost the backtest (close-to-close) does not model.