What if you'd held KOS?
A $1,000 investment in Kosmos Energy Ltd. Common Shares (DE) (KOS) at the month-end close of 2011-05 would be worth $154 at the close of 2026-08 — -84.6% total return, dividends reinvested. The same $1,000 in the S&P 500 would be worth $5,730.
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 2011
| Year | Value of $1,000 | Year return |
|---|---|---|
| 2011 | $1,000 | — |
| 2012 | $1,007 | +0.7% |
| 2013 | $912 | -9.5% |
| 2014 | $684 | -25.0% |
| 2015 | $424 | -38.0% |
| 2016 | $572 | +34.8% |
| 2017 | $559 | -2.3% |
| 2018 | $332 | -40.6% |
| 2019 | $479 | +44.2% |
| 2020 | $201 | -58.1% |
| 2021 | $296 | +47.2% |
| 2022 | $543 | +83.8% |
| 2023 | $573 | +5.5% |
| 2024 | $292 | -49.0% |
| 2025 | $77.74 | -73.4% |
| 2026 | $241 | +209.9% |
Best and worst month-end to buy
The best single month-end close to have bought KOS was 2020-03 ($0.90): $1,000 then is $3,133 today. The worst was 2011-05 ($18.28): $1,000 then is $154.
FAQ
What would $1,000 in KOS be worth today?
A $1,000 investment in Kosmos Energy Ltd. Common Shares (DE) (KOS) at the start of 2011 would be worth about $154 today, a total return of -84.6%. Dividends are reinvested in these figures.
What were the best and worst years for KOS?
Kosmos Energy Ltd. Common Shares (DE) (KOS)'s strongest calendar year since 2011 was 2026, a +209.9% return — $1,000 held through that year became about $3,099 by year-end. Its weakest year was 2025, at -73.4%.
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 KOS have grown?
Investing $100 at the end of every month since 2011-05 would have grown to about $11,931 on $18,400 invested.
Did KOS beat the S&P 500?
Over the same period, $1,000 in the S&P 500 index would be worth $5,730. KOS trailed the S&P 500 by +97.3% 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
Kosmos Energy Ltd. Common Shares (DE) (KOS) historical total-return data from 2011-05 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.