Sale of mutual funds that have unknown acquired date and unknown cost basis

[RHE1]

Sale of mutual funds that have unknown acquired date and unknown cost basis. when downloaded it is listed as as short term investment with o cost basis. Turbo tax is requiring that I review this but the form does not have the option of unknow for both of the acquired cost and purchase date. Should I just list it as short term and 0 cost? Very frustration its a vitious circle. 

[MarilynG1]

You can choose 'Various' under 'Something other than a date' when entering the acquired date.  However, you will need to enter a Cost Basis, which you may need to reconstruct from your own records.

Otherwise, the IRS will consider the cost basis as $0 and your proceeds will all be taxable, which you can choose to do. 

Historical prices of publicly traded stocks are  readily available on the internet and should, at least, satisfy the IRS that your basis wasn't zero; just "google" “Historical Stock Prices" or use http://bigcharts.marketwatch.com/historical/. The stockholder relations dept. at the company may be able to help.

@RHE1