`ticker` cannot uniquely identify a stock

Alphathon
#1

Hi all,


As told in the webinar and implied in the tutorial notebook, ticker from the table returned by getTickersSP500() is used to identify stocks. However, when I explore the data set I realize this was not the case. Some examples are “TT.US Equity”, “VAL.US Equity”. Stocks sharing the tickers have different company names and overlapping constituent period. Could someone please clarify this?


Thank you in advance for answering the question!


#2

Hi Lutaodai,


This is correct as stocks may be dropped out of the index and be included again.


To view the duplicated rows in R:

.sourceQlib()

df = getTickersSP500()

df[duplicated(df$ticker),]



To view the duplicated rows in Python:

import alphien

df = alphien.data.getTickersSP500()

df[df.duplicated([‘ticker’])]


Thank you.


#3

Hi Reiyun,


df[df["ticker"]=="TT.US Equity"] shows “TT.US Equity” corresponds to two companies:

  1. “Trane Inc.” listed from 2002-05-10 to 2008-06-5
  2. "Trane Techonologies plc" listed from 1970-01-01 to 2009-06-29 and 2010-11-16 to now

Similarly, df[df["ticker"]=="VAL.US Equity"] shows “VAL.US Equity” corresponds to two companies

  1. Ensco plc listed from 1970-0101 to 2009-12-21 and 2012-07-30 to 2016-03-28
  2. Valaris plc listed from 2007-01-03 to now

The reason why I believe in either example the ticker corresponds to two DIFFERENT companies is due to unexpected overlapping listed periods.


I suspect there is error in this table.

#4

Hi Lutaodai,


As mentioned in the thread: Alphien Dashboard. We have checked and corrected the dates.


Thank you!