Tax Audit Insurance Income Tax Question About Check From Insurance (mutual Fund) Company?

Income tax question about check from insurance (mutual fund) company? - tax audit insurance

I received an assurance on a share for 5 years. The insurance is sold is a form of ownership by the participants and the company was and the value will be distributed to policyholders in the form of shares of the acquiring company. I think it was a form of mutual funds, which will be paid. I have recently sold shares and have no idea how to determine the cost basis of shares. Today's society I can not say that the value of the stock on the date of publication (we do not know when), but not how much they spent before. I try, I find no prior information about the company or have an idea what to do. Certainly not want to pay sales tax on all who live upstream, but you do not know how to determine the cost basis and not verified and do not want to answer as precisely determine how much tax you to need.

What should I do, how can I determine the base cost for my tax file?