One combined rule. Zero discretion.

10-Month SMA Constant-Mix: compare the previous completed month's dividend-adjusted QQQ close with its trailing 10-month simple average. At or above the average, rebalance to the selected QQQ / T-bill target on the next month's first trading day. Below the average, sell QQQ and hold 100% 3-month T-bills.

The reference risk-on target is 75% QQQ / 25% T-bills. The slider changes that risk-on target; the risk-off target remains 0% QQQ / 100% T-bills. Trades are charged 10 basis points per 100% of portfolio turnover. The target is a drawdown-tolerance choice, not an optimized forecast.

Why the model specification changed (2026-07): deploying the whole hypothetical capital at once beat spreading it over 60 months in about 4 of 5 historical windows, and at matched average exposure a mechanical cash buffer protected the worst cases better than the signal-driven reserve it replaces — the signals fired at a real bottom exactly once in 27 years (2008-11 … 2009-04) and spent the reserve mid-crash in 2000–2002.

• Single-index concentration is the unhedged tail. The equity side is 100% Nasdaq-100. A Japan-1989-style multi-decade stagnation is not fixed by rebalancing, by schedules, or by signals — only by diversification, which this model deliberately does not do. That concentration is an explicit research assumption.
• Risk control has a return cost. In the 1963–2026 broad-market check, the trend rule reduced annualized return from 10.85% to 10.04% and terminal wealth from 668.8× to 421.0×. It nearly doubled the Calmar ratio, not terminal wealth.
• The website and the long-history check use different equity series. The research panel uses a broad U.S. equity total-return proxy. The interactive scenario uses QQQ from 2000 onward and defaults to a 75% risk-on cap. Its full available history produced a −27.5% monthly drawdown versus −79.6% for 100% QQQ, with terminal wealth 17% lower. Neither path establishes a future outcome.
• Turnover and tax matter. The simulations include 10bp per 100% of portfolio turnover, while taxes, bid-ask spread, fund fees and execution delay remain unmodeled. The broad-market trend rule turned over about 146% of portfolio value per year on average.
• The trend rule can whipsaw. The 8–12 month stability study found similar historical drawdown control, while the best-returning lookback changed across eras. Ten months is a fixed research choice, not a uniquely optimal parameter.
• Monthly granularity. Curves and drawdowns use one point per decision day; true intraday drawdowns run deeper.
• Specification history. The original three-signal model, TQQQ sleeve and 60-month deployment schedule were retired after independent re-tests. A fixed 75/25 mix followed. The current page adds the 10-month trend exit after a separate 1963–2026 broad-market study. Every version remains in the repository history.
• A backtest is not the future. This is public quantitative research. All capital, holdings and trades shown are hypothetical — not investment advice.