Here is my account history, trying to figure out what the W means in my history table.
END - ENDEAVOUR INTL CORP COM NEW
Legend says: "Adjusted due to previous wash sale disallowed loss." Can anyone explain what this means?
Well it would appear that you had a wash sale that canceled out a loss position. Without seeing the entire report, I couldn't tell you exactly what was happening or how you triggered § 1091. But just from the excerpted images, it appears as though your purchase of stock was layered into multiple tranches - perhaps you acquired more of the stock in the 61-day period than you sold (possibly because of a prior holding).
If in the 61-day period around the sale of stock (30 days before and 30 days after), you also acquire the same stock (including by contract or option), then it washes out your loss. If you held your stock for a while, then in a 61-day period bought more, and sold some, then any loss would be washed out by the acquisition. Of course it is also a wash sale if your purchase of the stock follows your sale, rather than precedes it. Your disallowed loss goes into the basis of your stock holding, so will be meaningful when you do have a true economic sale of that stock.
From IRS Pub 550:
A wash sale occurs when you sell or trade stock or securities at a loss and within 30 days before or after the sale you:
Buy substantially identical stock or securities,
Acquire substantially identical stock or securities in a fully taxable trade,
Acquire a contract or option to buy substantially identical stock or securities, or
Acquire substantially identical stock for your individual retirement account (IRA) or Roth IRA.
If you sell stock and your spouse or a corporation you control buys substantially identical stock, you also have a wash sale.
Looking at your excerpted account images, we can see a number of positions sold at a loss (sale proceeds less than basis) but each one is adjusted to a zero loss. I suspect the fuller picture of your account history and portfolio will show a more complicated and longer history with this particular stock. That is likely the source of the wash sale disallowed loss notations.
You might be able to confirm that all the added numbers are appearing in your current basis in this stock (or were reflected upon your final exit from the stock).
Summary of accepted answer: Your "loss" will not count as a loss (to the IRS). Which means no tax deduction for a "short-term capital loss" (on that sale).
Instead, the IRS simply pretends like you had paid less for the stock to begin with.