BIIBBIOGEN INC.— $500 a month, backtested
A dollar-cost-averaging backtest: a fixed amount (default $500 a month) invested into this stock on a fixed schedule, over real split- and dividend-adjusted (total-return) prices with dividends reinvested and no fees or taxes, compared against the same schedule into the S&P 500 (SPY) and a day-1 lump sum. Invested principal, end value and the money-weighted annualized return (XIRR) are engine-computed from historical prices, with no LLM. The Plan tab runs entirely in your browser on a return assumption you choose. The backtest is a historical statistic, not a prediction: past performance does not predict future results.
S&P 500 장기 평균 - 중립적인 출발점일 뿐 BIIB에 대한 예측이 아닙니다.
중요: 이 계산기의 예상치는 입력한 수익률 가정만으로 계산된 가상의 수치입니다. 실제 투자 결과를 반영하지 않으며 미래 성과를 보장하지 않습니다. 세금·수수료·인플레이션은 제외됩니다. 입력값에 대한 산술 계산일 뿐 - Tickwind의 예측이나 투자 자문이 아닙니다.
계산 방식
- 매월 초에 설정한 금액을 납입합니다 (0개월 차에 선택한 초기 일시금 포함).
- 잔액은 (1+r)^(1/12) − 1로 매월 복리 성장합니다. r은 위에서 설정한 연수익률입니다.
- 변동 밴드를 켜면 r ± 선택한 폭으로 같은 산술을 다시 계산합니다 - 통계적 신뢰구간이 아닙니다.
How the backtest works
- A fixed amount on a fixed schedule. Each monthly or weekly contribution is split across the basket at fixed weights and buys at that day’s adjusted close (fractional shares, no fees or taxes). There is no rebalancing: the basket drifts with performance, exactly like a real fixed-split auto-invest plan.
- Total return, not price-only. Prices are split- AND dividend-adjusted, so every curve already includes reinvested dividends.
- Buys execute on the first common trading day at or after each scheduled date across every basket ticker and SPY; a slot with no trading day of its own is skipped and disclosed - money is never silently doubled up.
- annualized (XIRR) is the money-weighted annual return that makes the dated contributions grow to the end value - the honest rate for a stream of contributions, where a simple CAGR would be wrong. It is omitted (—) on windows under a year rather than annualized misleadingly.
- The SPY row applies the identical schedule to the S&P 500 ETF; the lump-sum row shows the same total invested in the same basket on day 1 - the classic DCA-versus-lump-sum comparison, disclosed instead of implied.
- A historical backtest, not a forecast. A stat that cannot be computed honestly shows "—", never a fabricated 0. Past performance does not predict future results.
The backtest on this page is a disclosed historical statistic over real prices; the plan is hypothetical arithmetic on your inputs. Neither is a prediction, a price target, or investment advice. Past performance does not predict future results.