 This is Kevin Zivna, co-host of Dollars and Common Sense, with your financial planning tip. One of the biggest mistakes investors make is losing cost basis data, which is the amount paid to purchase an investment. When the investment is sold, only the profit is taxable, but you must retain proof of cost. Make sure you accurately record and retain this critical information. I'm Kevin Zivna of Wealthway Financial Advisors, planning for life. Wealthway Financial Advisors, planning for life.