Stock bought in May 2018. Dec 2018 the company was acquired & my stock changed to the new company. I sold the stock in Oct 2019. May 2018 should be the date acquired ?

[KatrinaB48]

The date you acquired the stock will be May of 2018. The change in company ownership does not affect the original purchase date.

[TomYoung]

The correct answer to your question depends entirely on if the acquisition was a taxable or non-taxable acquisition.  If it was a taxable acquisition then I'd expect you'd have received a 1099-B for 2018 in which case the new stock would have a Dec 2018 acquisition date.  Did you get a 2018 1099-B associated with the acquisition?  Names of companies involved?