Wall Street RegretsThe regret calculator.

What if you'd held PEN?

A $1,000 investment in Penumbra, Inc. (PEN) at the month-end close of 2015-09 would be worth $8,151 at the close of 2026-08 — +715.1% total return, dividends reinvested. The same $1,000 in the S&P 500 would be worth $4,015.

$1,000 since 2015$8,151Total return+715.1%Multiple8.2×CAGR+21.2%

Your scenario

Dates resolve to the nearest month-end close.
Leave empty for "held until today".
Invested at each month-end. Starts on the buy date.

Result

Worth$8,151Gain+$7,151 (+715.1%)Multiple8.2×CAGR+21.2%

    If you'd bought $1,000 at the start of each year

    Value of $1,000 invested on January 1 of each year, held to 2026-08, dividends included.

    2015$8,1512016$6,0742017$5,1232018$3,4732019$2,6752020$1,9902021$1,8682022$1,1382023$1,4692024$1,2992025$1,3762026$1,051

    Every year, $1,000 from 2015

    YearValue of $1,000Year return
    2015$1,000
    2016$1,186+18.6%
    2017$1,749+47.5%
    2018$2,271+29.9%
    2019$3,053+34.4%
    2020$3,252+6.5%
    2021$5,340+64.2%
    2022$4,134-22.6%
    2023$4,675+13.1%
    2024$4,413-5.6%
    2025$5,778+30.9%
    2026$6,074+5.1%

    Best and worst month-end to buy

    The best single month-end close to have bought PEN was 2015-10 ($37.03): $1,000 then is $8,826 today. The worst was 2026-01 ($358): $1,000 then is $913.

    FAQ

    What would $1,000 in PEN be worth today?

    A $1,000 investment in Penumbra, Inc. (PEN) at the start of 2015 would be worth about $8,151 today, a total return of +715.1%. Dividends are reinvested in these figures.

    What were the best and worst years for PEN?

    Penumbra, Inc. (PEN)'s strongest calendar year since 2015 was 2021, a +64.2% return — $1,000 held through that year became about $1,642 by year-end. Its weakest year was 2022, at -22.6%.

    Does the calculator include dividends and splits?

    Yes where available. Prices are adjusted for both stock splits and reinvested dividends (total return), the same measure brokerages use.

    How much would $100 per month in PEN have grown?

    Investing $100 at the end of every month since 2015-09 would have grown to about $31,387 on $13,200 invested.

    Did PEN beat the S&P 500?

    Over the same period, $1,000 in the S&P 500 index would be worth $4,015. PEN beat the S&P 500 by +103.0% in total return.

    Is this investment advice?

    No. Wall Street Regrets is an entertainment and education tool. Every number is a historical calculation, not a prediction, and past performance never guarantees future results.

    Methodology

    Penumbra, Inc. (PEN) historical total-return data from 2015-09 to 2026-08, reduced to month-end closes for the tables above.

    Returns use adjusted close prices from Yahoo Finance historical data — adjusted for stock splits and reinvested dividends — the same convention used by major brokerages. A "year" scenario invests $1,000 at the prior December's month-end close and values it at the latest available month-end close. Non-USD amounts are converted at historical month-end exchange rates (Yahoo Finance): to USD on the buy date and back to your currency at the latest rate, so the return reflects the currency move as well as the asset.

    Month-end resolution means intra-month extremes are not captured in tables; the calculator uses exact trading-day closes where daily data is available. Figures ignore taxes, fees, and the currency effects of non-USD listings. History is not a forecast. Wall Street Regrets is entertainment, not investment advice.

    Full methodology →

    What if you'd held…

    Data: adjusted close prices via Yahoo Finance. As of 2026-08. Not financial advice.