Brokerage Web Tax Lot Selector Overlay

WHAT IT DOES This userscript helps investors make tax-efficient selling decisions by enhancing the tax lot selection interface on brokerage pages. It scans brokerage order entry and tax lot selection pages to extract available tax lots—including purchase date, quantity, cost basis, current price, and unrealized gain/loss. It then displays an enhanced panel where you can select individual lots with clear visual indicators of gain/loss, holding period (short-term vs long-term), and estimated tax impact based on your tax bracket. The script highlights lots with the highest capital gain or loss, provides recommendations like "Sell to realize gain" or "Harvest loss," and shows the aggregate gain/loss of selected lots. This helps you achieve specific tax outcomes, such as harvesting losses to offset gains. WHERE IT RUNS The script works on brokerage order entry and tax lot selection pages—commonly found on platforms like Fidelity, Vanguard, Schwab, E*TRADE, TD Ameritrade, Robinhood, and similar brokerages. It runs entirely within your browser, reading only the visible content of the current page. It does not track your browsing history, access other tabs, or send any data externally. All calculations are performed locally. HOW TO USE After installation, open the panel by clicking the tool's icon in the BotGentz sidebar. Select your tax bracket (0%, 10%, 15%, 20%, or 25%) to get accurate tax impact estimates. The script auto-scans tax lot pages on load (toggle this on/off). Click "Scan tax lots" to manually analyze the page. The panel displays each tax lot with its purchase date, quantity, holding period, gain/loss, estimated tax impact, and a recommendation. Check the boxes next to lots you want to select—the summary updates in real time showing total shares and aggregate gain/loss. Use "Clear selector" to remove the display. THE TECHNICAL MECHANISM This script uses DOM traversal and pattern matching to extract tax lot data from brokerage pages. It scans for tax lot elements using common selectors like .tax-lot, .lot, .position, [class*="lot"], and [class*="tax"]. For each element, it extracts purchase dates using regex patterns for MM/DD/YYYY, YYYY-MM-DD, and named month formats; quantities using patterns like "X shares"; cost basis using "Cost basis: $X"; gain/loss using patterns like "Gain/Loss: $X"; and current price. The script calculates holding period as short-term (