I am extracting the opening price of a stock, say "AAPL"(Apple Inc) using yfinance. I come across something very interesting, yet confusing details. I have used two methods to obtain the opening price of the stock, yf.Ticker and yf.download.
apple1 = yf.Ticker("AAPL")
apple2 = yf.download("AAPL")
As you can see in the dataframe below, the opening price for both methods shows totally different prices. Any idea what's happening here?
hist = apple1.history(period="max")
hist["Open"][:100]
Out[97]:
Date
1980-12-12 0.100323
1980-12-15 0.095525
1980-12-16 0.088546
1980-12-17 0.090291
1980-12-18 0.092908
1981-04-30 0.099015
1981-05-01 0.099015
1981-05-04 0.099015
1981-05-05 0.098578
1981-05-06 0.095962
Name: Open, Length: 100, dtype: float64
apple2["Open"][:100]
Out[98]:
Date
1980-12-12 0.128348
1980-12-15 0.122210
1980-12-16 0.113281
1980-12-17 0.115513
1980-12-18 0.118862
1981-04-30 0.126674
1981-05-01 0.126674
1981-05-04 0.126674
1981-05-05 0.126116
1981-05-06 0.122768
Name: Open, Length: 100, dtype: float64
history() allows you to set the auto_adjust=False parameter, which deactivates adjustments on OHLC (Open/High/Low/Close prices). By default, adjustments are enabled.
For download() adjustments are disabled by default.
If disabled for history(), both variants lead to the same result:
hist = apple1.history(period="max", auto_adjust=False)
hist["Open"][:100]
apple2 = yf.download("AAPL")
apple2["Open"][:100]
Equally, auto_adjust can also be enabled for download(). Which then yields the same (adjusted) results.
hist = apple1.history(period="max")
hist["Open"][:100]
apple2 = yf.download("AAPL", auto_adjust=True)
apple2["Open"][:100]