What if you'd held CLLS?
A $1,000 investment in Cellectis S.A. (CLLS) at the month-end close of 2015-03 would be worth $91.67 at the close of 2026-08 — -90.8% total return, dividends reinvested. The same $1,000 in the S&P 500 would be worth $3,727.
Your scenario
Result
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.
Every year, $1,000 from 2015
| Year | Value of $1,000 | Year return |
|---|---|---|
| 2015 | $1,000 | — |
| 2016 | $546 | -45.4% |
| 2017 | $939 | +72.0% |
| 2018 | $537 | -42.9% |
| 2019 | $552 | +2.8% |
| 2020 | $872 | +58.1% |
| 2021 | $262 | -70.0% |
| 2022 | $67.68 | -74.1% |
| 2023 | $99.26 | +46.7% |
| 2024 | $58.01 | -41.6% |
| 2025 | $156 | +168.9% |
| 2026 | $102 | -34.5% |
Best and worst month-end to buy
The best single month-end close to have bought CLLS was 2023-10 ($0.97): $1,000 then is $3,268 today. The worst was 2015-05 ($42.90): $1,000 then is $73.89.
FAQ
What would $1,000 in CLLS be worth today?
A $1,000 investment in Cellectis S.A. (CLLS) at the start of 2015 would be worth about $91.67 today, a total return of -90.8%. Dividends are reinvested in these figures.
What were the best and worst years for CLLS?
Cellectis S.A. (CLLS)'s strongest calendar year since 2015 was 2025, a +168.9% return — $1,000 held through that year became about $2,689 by year-end. Its weakest year was 2022, at -74.1%.
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 CLLS have grown?
Investing $100 at the end of every month since 2015-03 would have grown to about $8,863 on $13,800 invested.
Did CLLS beat the S&P 500?
Over the same period, $1,000 in the S&P 500 index would be worth $3,727. CLLS trailed the S&P 500 by +97.5% 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
Cellectis S.A. (CLLS) historical total-return data from 2015-03 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.
What if you'd held…
Data: adjusted close prices via Yahoo Finance. As of 2026-08. Not financial advice.