This expert commentary will appear in a major rewrite of our guide "Selling Stock to Buy a House," targeting home buyers with $50K–$500K in brokerage accounts considering liquidation for a down payment. Questions: 1. What's the most expensive tax mistake you've seen a client make when selling stock for a home purchase? We're looking for a specific scenario — wrong account type, didn't use specific identification, triggered short-term gains unnecessarily, etc. 2. When a borrower's down payment comes from a recent stock sale, what changes about the mortgage underwriting process? What documentation do lenders require, how far in advance should the borrower liquidate, and what happens when a large deposit from a stock sale appears without a proper paper trail? 3. At what portfolio size does borrowing against stock (SBLOC, pledged-asset mortgage, margin loan) start to make more sense than selling? We want real thresholds, current rate comparisons, and the honest risks — especially margin call scenarios. 4. For someone with ESPP or RSU stock who wants to buy a home, what's the one thing they need to understand about their tax situation that's different from selling regular brokerage stock? 5. What's your advice for a client who is emotionally afraid to sell stock they've held for years, even though they need the money for a home? We're looking for the psychological framing, not just the math.