How do I establish the cost basis of shares bought in an employee stock purchase program?
A public company should have a link for investor relations, which should help provide a trail of basis if this is a matter of company buyout, takeover, etc.  This gets you close, but if you don't have an exact date, it will just be close, not exact.  One clean way out of this, assuming the goal is to get rid of the stock and move on, is to donate the shares to charity. You will take the present value as a deduction, and be done. You can use a charitable gift fund such as those offered by Schwab or Fidelity, so if say, the shares are worth $20K, and you typically donate $5K per year, the fund lets you do this transaction at once, then send to the charities you wish over the next few years.
"I dug up an old article on Motley Fool and one approach they mention is to get the stock certificates and then sell them to a friend: If the company was liquidated, you should receive a 1099-DIV form at    year's end showing a liquidating distribution. Treat this as if you   sold the stock for the amount of the distribution. The date of ""sale""   is the date that the distribution took place. Using your original cost   basis in the shares, you can now compute your loss. If the company hasn't actually been liquidated, you'll need to make   sure it's totally worthless before you claim a loss. If you have   worthless stock that's not worth the hassle of selling through your   broker, you can sell it to a friend (or cousin, aunt, or uncle) for   pennies. (However, you can't sell the stock to a spouse, siblings,   parents, grandparents, or lineal descendants.) Here's one way to do   it: Send the certificate to your stock-transfer agent. Explain that the shares have been sold, and ask to cancel the old shares and issue   a new certificate to the new owner. Some brokerages will offer you a quicker alternative, by buying all of your shares of the stock for a penny. They do it to help out   their customers; in addition, over time, some of the shares may   actually become worth more than the penny the brokers paid for them. By selling the shares, you have a closed transaction with the stock and can declare a tax loss. Meanwhile, your friend, relative, or   broker, for a pittance, has just bought a placemat or birdcage liner." Owning a stock via a fund and selling it short simultaneously should have the same net financial effect as not owning the stock.  This should work both for your personal finances as well as the impact of (not) owning the shares has on the stock's price. To use an extreme example, suppose there are 4 million outstanding shares of Evil Oil Company.  Suppose a group of concerned index fund investors owns 25% of the stock and sells short the same amount.   They've borrowed someone else's 25% of the company and sold it to a third party.  It should have the same effect as selling their own shares of the company, which they can't otherwise do.  Now when 25% of the company's stock becomes available for purchase at market price, what happens to the stock?  It falls, of course.   Regarding how it affects your own finances, suppose the stock price rises and the investors have to return the shares to the lender.  They buy 1 million shares at market price, pushing the stock price up, give them back, and then sell another million shares short, subsequently pushing the stock price back down. If enough people do this to effect the share price of a stock or asset class, the managers at the companies might be forced into behaving in a way that satisfies the investors.  In your case, perhaps the company could issue a press release and fire the employee that tried to extort money from your wife's estate in order to win your investment business back.  Okay, well maybe that's a stretch. No. If you didn't specify LIFO on account or sell by specifying the shares you wish sold, then the brokers method applies.  From Publication 551 Identifying stock or bonds sold.   If you can adequately identify the   shares of stock or the bonds you sold, their basis is the cost or   other basis of the particular shares of stock or bonds. If you buy and   sell securities at various times in varying quantities and you cannot   adequately identify the shares you sell, the basis of the securities   you sell is the basis of the securities you acquired first. For more   information about identifying securities you sell, see Stocks and   Bonds under Basis of Investment Property in chapter 4 of Pub. 550. The trick is to identify the stock lot prior to sale. "I have some money invested on Merrill Edge. 2 days ago I purchased some mutual funds with most of the rest of my money in my account. I logged in today to see how it did, and noticed that there are 3 sections: Priced Investments, Cash &amp; Money Accounts, and Pending Activity. In the Cash &amp; Money section, there shows a negative balance of Cash (let's say -$1,000) and a positive ""Money Account Value"" (let's say +$1,100).  The ""Money Account"" appears to be made up of $1 shares of something called ""ML Direct Deposit Program"". However, even though the mutual fund purchase was made 2 days ago, and the shares of the mutual funds are officially in my account, I'm still showing all of my ""Money Account"" shares ($1000). The balance sheet effectively makes it look like I somehow needed to have ""sold"" back my money account shares, converted them to cash, and then bought the funds. I'm hoping that isn't the case, and for some reason, there is a multiday lag between me buying stock and money getting deducted from my ""Money Account"". Hope that all makes sense.  TLDR: what's the diff between a Cash account and Money Account that's filled with shares of "" ML Direct Deposit Program""?  Edit: Today the cash and money account offset by equal values equal to one of my mutual fund purchases." "Have the stock certificate in with a letter from the previous owner of the company from what I can tell in the letter these stocks were distributed from the owner himself stating ""after evaluation we have determined that your investment in this company is worth 10,000 shares at $1.00 a piece"" as well as I believe these shares were also acquired when the company was going through name changes or their company was bought" What I do have is this (sample only): Stock X: Average Price of all I purchased before = 80 Total Shares = 200 So if Stock X's price today is 100 how do I know how much my average price will be? Using your sample if you buy 100 new shares and the price is 85 for the purpose of this example your previous total cost is $16,000 ($80 average cost * 200 shares).  With the new example you are adding $8500 to your total cost (100 new shares * $85 example cost per share)  that gives us a total cost of $24,500 and 300 shares. $24,500/300 gives us an average cost of $81.67 per share. As long as you have the average cost and the number of shares you can calculate a new average without knowing what the price was for each transaction. It may still become important to find the price information for tax purposes if you do not sell all of those shares at once and use FIFO for your taxes. If the gift was stock that they have owned for years there can be one hitch: The basis of the stock doesn't reset when it is gifted. For example if grandparents have owned stock that is currently worth $10,000 today, but they bought it decades ago when it only cost them $1,000; then if the new owner sells it today they will have a gain of $9,000. The clock to determine short term/long term also doesn't reset; which is good. The basis needs to be determined now so that the gain  can be accurately calculated in the future. This information should be stored in a safe place. Gains for dividends are investment income and the rules regarding the kiddie tax need to be followed. "The shares are ""imputed income"" / payment in kind. You worked in the UK, but are you a ""US Person""? If not, you should go back to payroll with this query as this income is taxable in the UK. It is important you find out on what basis they were issued. The company will have answers. Where they aquired at a discount to fair market value ? Where they purchased with a salary deduction as part of a scheme ? Where they acquired by conversion of employee stock options ?    If you sell the shares, or are paid dividends, then there will be tax withheld."