Cost Basis
The price you originally paid for an asset — the anchor for both your tax bill and your psychology.
Cost basis is what you paid to acquire an asset, including fees. It determines your capital gain or loss when you sell (sale price minus cost basis) and is therefore central to crypto taxes — jurisdictions require you to track it across every buy, sell, swap and reward.
On-chain, aggregate cost basis (via realized price) becomes a market-wide behavioral anchor: holders resist selling below their cost, creating support, and rush to “break even” near it, creating resistance. Cost-basis tracking is also a practical headache — swaps and DeFi interactions each create taxable events with their own basis, which is why crypto tax software exists. Keep records from your first purchase.