The issuer of the IRS form 1099-B either does not have the information or is not required to report the information. Even though there is no date of acquisition, does it report either long-term or short-term?
Are you able to find the date acquired by reviewing your internal records and sales tickets?
The dates of purchase and sale are used to determine long-term or short-term investments.
- Short-term gains or losses come from the sale of investments owned one year or less.
- Long-term gains or lossses come from the sale of investments held more than one year.
As a rule, tax rates are more attractive for long-term investments.