Spikes in Data

[samikm]

Hi ,
I downloaded the data for ticker RELIANCE.NS .

I find that there are a few spikes in the data around 2005. I was wondering what are these as I don't find the spikes in the data on yahoo website for the same stock ->
https://finance.yahoo.com/quote/RELIANCE.NS/

I need the data for a college project. Can you please tell me why the spikes are there ?

Regards,
Samik

[ValueRaider]

Did you compare against Historical Data page? That's where YF gets prices.

Do spikes still show without dividend adjustment?

[samikm]

Thanks for your kind response.

1. In the historical data section on the yahoo finance web page , I only find data for the past 1 year i.e. is from 22-Jan-2025 to 22-Jan-2026. I am unable to find the data for periods going to 2004 to 2008 on the website which I need to compare Vs my downloaded data. In my downloaded data , I found spikes in this region.
2. In yfinance.download method call for reliance.ns , I am not finding the "adjusted closing price". Maybe I am seeing the spikes because I plotted closing price instead of adjusted closing price ? I am attaching my code. Would you find taking a look into it ?
   a) List of Nifty50 top stocks in csv
   b) Python code that reads this stickers in the csv to download data
   c) Output file STOCKS3.xlsx -> no "adjusted closing price" seen in the headers for 'RELIANCE.NS'
   ind_nifty50list.csv
   yahoo_data_download2.py
   Uploading STOCKS3.xlsx…

I am new to algo trading and now very little about stock market. It would greatly help me for my college project if you don't mind taking a look.

Regards,
Samik

[samikm]

Not sure if the output file 'STOCKS3.xlsx' is getting uploaded , since it's size is big. If you place the other two in the same folder and execute the python file , you would get the output file.

[ValueRaider]

I only find data for the past 1 year i.e. is from 22-Jan-2025 to 22-Jan-2026

Skill issue. The data is there.

[samikm]

Dear Sir,
Thank you for your kind response.
I changed my call to the api by including auto_adjust=False , in
df = yfinance.download(list_tickers, start="1950-01-01", end="2026-01-01", auto_adjust=False);
This was not mentioned in the documentation.
Now , I am getting the Adjusted closing price. However , a web search says that this is same as the previous closing price with this option set to True. Indeed on plotting the data , I see the same trend with the spike around 2004-2008. I believe the adjusted closing price to compensate for stock splits and dividends. Therefore , I do not understand why there are still spikes ? Would greatly appreciate your valuable opinion.

Regards,
Samik