Unrealised gains or losses exist on paper — they reflect the difference between your cost basis and the current market value of holdings you haven't sold yet. They only become "realised" when you sell.
Unrealised Gain = Current Market Value - Cost Basis (for unsold positions)
You bought 100 shares at $50 ($5,000 cost basis). They're now worth $75 each ($7,500). Your unrealised gain is $2,500 — no tax is owed until you sell.
AllInvestView shows unrealised gains/losses on your dashboard. Learn about tax-loss harvesting to use losses strategically.