SPDR is an ETF or index fund that had first started in the market in 1993. These funds are initially based off the S&P 500 which hold a stake in the 500 stocks represented in the S&P. These are traded on the secondary market but can be purchased by the net asset value at the time of purchase. The average return for this ETF throughout its life is .8% monthly. this means on average you will gain .8% on your ETF each month. The standard deviation calculated throughout its life was .4%. These calculations however are only averages and will not be the outcome for each actual month, so in order to give a better generalization as to what kind of return will be found, I ran a simulation for the total return after 360 months of investing $500 100 separate times.
The average total portfolio after the 100 simulations came out to $1.8 million. This calculation does not involve worse case or best case scenario, so in order to find that I found the upper and lower ranges to find the best and worst outcomes. For the lower range, I found a loss of $233,000 which is a .025/100 chance of occuring, with the upper range or best case scenario coming to $2.6 million. The chances of landing in between these two numbers are extremely high.
In some cases, such as in 2008 with the great recession, numbers can fall greatly. This is highly unlikely to occur but it is important to know the risk. This is known as the Fat tail, or situations that aren't calculated in a normal distribution. After running the numbers to a similar outcome of the great recession, An average return could amount to -16% of the total investment. This however has a .0025/100 chance of occurring.
SPDR is a very concrete ETF that holds a higher chance of pulling a profit at a smaller chance. This is a good ETF to invest in for people who are looking for long-term growth with little risk.