The key distinction is paper versus realized. An impairment doesn't mean the company sold anything, lost custody of anything, or changed strategy — it means the accountants compared the asset's market value to what's on the books and booked the difference as a loss.
Tesla's $112 million Q2 charge on 11,509 unmoved BTC is the textbook case: same coins, smaller income statement.
The rules have evolved. Under the old US GAAP treatment, bitcoin was an "indefinite-lived intangible": companies had to write it down whenever price dipped but could never write it back up until they sold — a one-way ratchet that made corporate earnings look worse than the position. Fair-value accounting fixed the asymmetry: holdings are now marked to market each quarter, so down quarters produce losses and up quarters produce gains. That symmetry is exactly what makes every
bitcoin treasury company's quarterly report a bitcoin price report in disguise.