Hello,
I’ve been an Alpaca user for a long time now, but I think its the first time I post on the forum.
I’m currently testing the prices feed of another data provider and found some differences with your feed. More specifically, differences when adjusting prices by dividends. Differences that may be small in the dates closer to the present day, but large when looking back a couple years ago.
I wanted to show you a couple examples and ask you why these differences exist.
Example 1 - AAPL:
Dates: 1/1/2021-
From January 1st, 2021, until now, there’s been 16 dividend payments. Ranging from $0.205 to $0.250. There haven’t been any splits between these dates.
When considering dividends, as you already know, we need to consider all payments from the starting date until the present day.
Considering these dividends, the adjusted close price for January 4th, 2021, returns $126.54 both for the provider I’ve been testing and for yahoo finance adjusted close. However, for Alpaca it’s $126.37.
Doing some tests, I saw that for recent prices, say November 6th, 2024, the difference between these adjusted prices is way smaller, of 0.01 ($222.48 in yahoo finance and this provider vs $222.47 in Alpaca). I believe this is caused because of the way you round the third decimal. If the adjusted price is $222.4751, you don’t round it up to $222.48. Instead, you leave it as $222.47.
Besides this rounding difference, is there a reason for such a large difference in older dates?
Example 2 – OLP:
Dates: 1/1/2020-
This stock is cheaper than AAPL, I wanted to use it as an example so you can see how the differences now represent a higher value as a percentage of the price.
From January 1st, 2020, until now, there’s been 19 dividend payments.
If we look at January 8th, 2020, the price that the provider and yahoo finance return is of $18.85. Alpaca returns $18.08. There are 80 cents of difference, almost 5%.
Given these examples, I’d like to ask you what is causing these differences. Are you considering some dividends we may not be considering? Are you adjusting differently than normal?
Please let me know!
Thanks,
Martin
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