I thought Yahoo Finance would have this data, but they actually only
go back about a year or so.
However, with a bit of searching, I came across the very aptly named
site, Earnings.com, with records going back to 2000, at least:
In the upper right corner is a text box where you can type in the
company name or symbol of interest to you, and the search results will
return a table that includes earnings dates.
For instance, I searched on YHOO (why not?) and got results with two
tables -- webcast dates on top, followed by a table with earnings
dates that spanned a period from 1999 to present:
The information includes the time of earnings release, either with a
'clock' time (e.g. 4:15 pm) or by indicating AMC, for 'after market
close' -- other stocks may also use BMO for 'before market opens'.
I trust this information fully meets your needs. But please don't
rate this answer until you are completely satisfied with the results.
If you have any questions, just post a Request for Clarification to
let me know how I can further assist you.
search strategy -- Google search on [ earnings dates ]