What if you'd held SEIC?
A $1,000 investment in SEI Investments Company (SEIC) at the month-end close of 1981-03 would be worth $761,418 at the close of 2026-08 — +76041.8% total return, dividends reinvested. The same $1,000 in the S&P 500 would be worth $56,676.
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 1981
| Year | Value of $1,000 | Year return |
|---|---|---|
| 1981 | $1,000 | — |
| 1982 | $1,594 | +59.4% |
| 1983 | $2,080 | +30.5% |
| 1984 | $1,166 | -44.0% |
| 1985 | $1,920 | +64.7% |
| 1986 | $1,508 | -21.4% |
| 1987 | $2,775 | +84.0% |
| 1988 | $2,872 | +3.5% |
| 1989 | $2,930 | +2.0% |
| 1990 | $3,578 | +22.1% |
| 1991 | $4,310 | +20.5% |
| 1992 | $5,278 | +22.5% |
| 1993 | $8,754 | +65.9% |
| 1994 | $5,754 | -34.3% |
| 1995 | $7,289 | +26.7% |
| 1996 | $7,497 | +2.9% |
| 1997 | $14,219 | +89.7% |
| 1998 | $33,711 | +137.1% |
| 1999 | $40,412 | +19.9% |
| 2000 | $114,497 | +183.3% |
| 2001 | $92,417 | -19.3% |
| 2002 | $55,968 | -39.4% |
| 2003 | $62,893 | +12.4% |
| 2004 | $87,316 | +38.8% |
| 2005 | $77,508 | -11.2% |
| 2006 | $125,358 | +61.7% |
| 2007 | $135,727 | +8.3% |
| 2008 | $66,642 | -50.9% |
| 2009 | $75,412 | +13.2% |
| 2010 | $103,305 | +37.0% |
| 2011 | $76,422 | -26.0% |
| 2012 | $105,861 | +38.5% |
| 2013 | $159,631 | +50.8% |
| 2014 | $186,406 | +16.8% |
| 2015 | $246,321 | +32.1% |
| 2016 | $234,535 | -4.8% |
| 2017 | $344,749 | +47.0% |
| 2018 | $224,380 | -34.9% |
| 2019 | $321,652 | +43.4% |
| 2020 | $285,963 | -11.1% |
| 2021 | $307,070 | +7.4% |
| 2022 | $298,037 | -2.9% |
| 2023 | $329,599 | +10.6% |
| 2024 | $433,326 | +31.5% |
| 2025 | $436,059 | +0.6% |
| 2026 | $574,118 | +31.7% |
Best and worst month-end to buy
The best single month-end close to have bought SEIC was 1981-03 ($0.14): $1,000 then is $761,418 today. The worst was 2026-08 ($107): $1,000 then is $1,000.
FAQ
What would $1,000 in SEIC be worth today?
A $1,000 investment in SEI Investments Company (SEIC) at the start of 1981 would be worth about $761,418 today, a total return of +76041.8%. Dividends are reinvested in these figures.
What were the best and worst years for SEIC?
SEI Investments Company (SEIC)'s strongest calendar year since 1981 was 2000, a +183.3% return — $1,000 held through that year became about $2,833 by year-end. Its weakest year was 2008, at -50.9%.
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 SEIC have grown?
Investing $100 at the end of every month since 1981-03 would have grown to about $5.04M on $54,600 invested.
Did SEIC beat the S&P 500?
Over the same period, $1,000 in the S&P 500 index would be worth $56,676. SEIC beat the S&P 500 by +1243.5% 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
SEI Investments Company (SEIC) historical total-return data from 1981-03 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.