Why did the cost basis of my position change?

Cost basis is the original value of a security or other asset used for tax purposes to determine whether a capital gain or loss has been realized when that asset is sold or disposed. Depending upon the tax regulations, the cost basis may be adjusted for commissions, wash sales or corporate actions such as stock splits and return of capital distributions…

Your statement is likely not reflecting your loss due to a “wash sale” A sale of stock or securities is considered a "wash sale" if a trader sells shares or securities at a loss and purchases the same or equivalent shares or securities within the 61-day wash sale period, which includes the 30 calendar days before the sale, the day of the sale, and 30 calendar days following the sale. When the loss on the sale is deferred, the amount of the loss is added to the cost basis of shares purchased during the wash sale period ("replacement shares"). Upon the sale of the replacement shares, the disallowed loss is incorporated into the calculations of the gain or loss on the replacement shares and recognized. Additionally, the holding period of the original shares is added to the holding period of the newly acquired shares or securities…

Dividends are not included in a positions P&L calculation. However, if the dividend was actually designated as a Return of Capital distribution, then this would reduce the cost basis of the shares owned and affect the realized/unrealized P&L of the position…

The Box 1e of Form 1099-B reports cost or other basis of securities sold. This basis may be adjusted for wash sales, related options positions, and corporate actions. Box 1e is not used for reporting sales of uncovered securities as cost basis is not reported for these sales…