Magnificent 7 Stocks Calculator - Investment Backtest

What is a Magnificent 7 stocks backtest

A backtest replays your contribution schedule against actual historical prices to show what would have happened, not what will happen. This calculator uses monthly closing prices from Yahoo Finance to compound returns period by period. The result is a year-by-year record of how your invested amounts interacted with real market movements for the stock you selected.

How the model builds your results

Each month the calculator applies the stock's actual price change to your running balance, then adds your contribution for that month. Contributions across all frequencies are converted to an equivalent monthly flow before being added.

• Returns: derived from consecutive monthly closing prices. A month where the stock rose 10% adds 10% to your balance before the contribution lands.
• Compounding: applied every month to the full running balance including past growth. Growth earns growth from the next month onward.
• Contributions: seven frequencies are supported: daily (365/yr), weekly (52/yr), biweekly (26/yr), semimonthly (24/yr), monthly (12/yr), quarterly (4/yr), and annual (1/yr). Each is normalized to an equivalent monthly amount before being added to the balance.
• Returns: when dividend reinvestment is off (default), results reflect price returns only. When it is on, dividend payments from Apple or Microsoft are added to that month's rate and compounded — the dividend column in the yearly table shows the cumulative amount reinvested.
• Extension: if your end year goes beyond the last available data point, the assumed annual return you enter is converted to a monthly rate and applied from that point onward.

Supported stocks and date coverage

The calculator covers all seven stocks in the Magnificent 7: Apple (AAPL) with data from 1984, Microsoft (MSFT) from 1986, Amazon (AMZN) from 1997, NVIDIA (NVDA) from 1999, Alphabet (GOOGL) from 2004, Tesla (TSLA) from 2010, and Meta (META) from 2012. The minimum start year selector adjusts automatically when you switch stocks. For comparisons across all seven, a common start year of 2013 or later covers every stock with a full calendar year of data.

Worked example

Suppose you started with $1,000 and added $100 per month in Apple stock from January 2015 to December 2024. Over those 10 years you would have made 120 monthly purchases on top of your starting amount. The calculator compounds each month's actual AAPL price return on the running balance, adds your $100, and tracks the outcome year by year. The yearly breakdown lets you see exactly which years, including the strong bull runs of 2019 and 2023, contributed most to the final portfolio value.

Stock volatility and what it means for your results

The Magnificent 7 are large-cap technology stocks, but they are still significantly more volatile than broad index funds. NVIDIA lost approximately 66% of its value in calendar year 2022, then returned roughly 239% in 2023. Meta fell about 64% in 2022 alone before recovering strongly in 2023. Tesla dropped around 65% in 2022. These swings appear in the yearly breakdown as large positive or negative growth rows. A longer backtest window averages across multiple market cycles and usually produces a more stable trend line than a single-year view.

Dividend reinvestment

Toggle "Reinvest dividends" under More options to add real per-share dividend payments to your monthly compounding. Apple pays approximately $0.25 per share per quarter (roughly 0.5% annually); Microsoft approximately $0.75 per share per quarter (roughly 0.8% annually). When the toggle is on, each dividend payment is expressed as a yield fraction of the previous month's price and added to that month's return, then compounded into the running balance. Over a 20-year horizon starting with $1,000 and $100/month, enabling dividend reinvestment for Apple adds roughly $2,000–4,000 to the final balance compared to price-only — the exact amount depends on the start year and share price at each payment date. Alphabet, Amazon, Tesla, NVIDIA, and Meta pay no regular cash dividend; enabling the toggle for these stocks has no effect.

Transaction costs

Use the "Transaction cost" field under More options to model a flat brokerage fee charged each time a contribution event occurs. The fee is deducted from the effective contribution before it is added to the balance, so it reduces both the principal and the compounding base. A $5 fee on a $100 monthly contribution means only $95 is invested each month. Over 20 years at monthly frequency that is $1,200 in foregone principal — not including the opportunity cost of that capital not compounding. At quarterly frequency the same $5 fee costs only $300 over 20 years, since there are four events per year instead of twelve. Most major online brokers now offer commission-free US stock trading, so for many users this field will remain at zero.

Annual contribution increase

The "Annual contribution increase" field under More options lets you model growing contributions over time — a common pattern when income rises with career progression. Two modes are available:

• Percentage: contributions compound annually. At 3% per year, a $100/month base becomes $103/month in year 2, $106.09 in year 3, and so on. Over 20 years the final-year monthly contribution reaches approximately $175.
• Fixed amount: contributions increase by a flat annual sum divided across 12 months. A $600/year increase adds $50/month each year linearly — $150/month in year 2, $200/month in year 3. Unlike the percentage mode this increase is additive, not multiplicative.

Extending the projection beyond historical data

Set "Assumed return after last data year" to a percentage if you want to continue the projection past available history. A 7% annual assumption converts to approximately 0.57% per month. Setting it to 0% freezes market growth after the data ends and only adds contributions. Try 0%, 5%, and 10% to see how sensitive the long-term outcome is to your assumed future rate.

Reading the results

• The yearly breakdown table shows contributions deposited and market-driven growth for each calendar year, plus the year-end balance.
• The stacked chart splits total value into starting amount, cumulative contributions, and cumulative growth at each year-end. When the growth slice exceeds contributions, compounding is doing most of the work.
• The summary panel shows your final portfolio value, total amount contributed, and total growth so you can immediately see the return above cost.

Usage tips

• Compare stocks over the same window: keep start and end year fixed, then switch stocks to see how different Mag 7 companies behaved under the same contribution schedule.
• Use longer horizons: windows of 1 to 2 years are often dominated by a single market cycle. Windows of 5 years or more show compounding and cost-averaging working together.
• Test future scenarios: extend the end year beyond available data and try different assumed returns to explore the range of possible outcomes.
• Reinvest dividends: enable the dividend toggle for Apple or Microsoft under More options to see the historical total return including dividends.

Important limitations

• Prices come from Yahoo Finance monthly closing data and reflect split-adjusted prices. By default results show price returns only. Enable dividend reinvestment under More options to include per-share dividend data for Apple and Microsoft.
• Trading fees, brokerage commissions, capital gains taxes, and spread costs are not modeled. On a $100/month plan with a 0.05% fee, that is $0.05 per trade, small individually but compounding over many years.
• Currency display is for visual context only. Historical foreign exchange rates are not reconstructed, so numbers assume you held and measured in USD throughout.
• Past stock performance does not predict future returns. A stock that returned 500% over one decade may behave very differently in the next.
• Concentration risk: investing in a single stock carries significantly higher risk than a diversified portfolio. The Magnificent 7 represent a narrow slice of the market despite their large combined weight in major indices.

Supporting calculators

• Real purchasing power: use the Inflation Calculator to translate your historical Mag 7 portfolio values into today's purchasing power and understand what your nominal gains are worth in real terms after decades of price rises.
• Alternative asset comparison: use the Metals Investment Calculator to run the same contribution schedule on gold, silver, or other metals, so you can directly compare how hard assets would have behaved over the same years.
• Digital asset comparison: use the Crypto Investment Calculator to backtest the same DCA schedule on Bitcoin or Ethereum and see how alternative digital assets compare to Magnificent 7 price performance.

Learn more

• Data transparency: read the Calculator Data Guide to understand where stock price data comes from, how monthly price history is updated, and how it is converted into calculator results.