December receives most of the attention because capital transactions must generally occur within the tax year to affect that year. But waiting until year-end can compress decisions, increase wash-sale risk, and miss losses that appeared earlier.
Events that can trigger a review
- A sharp market decline or loss in a concentrated position
- A business sale, asset sale, real-estate sale, or large stock-compensation event
- Mutual-fund capital-gain distributions
- A move to another state
- A portfolio rebalance
- New capital-loss carryover information from the completed return
What year-round review improves
More time allows the taxpayer and advisor to verify basis, review multiple accounts, identify automatic purchases, model state effects, and assess replacement investments without a year-end rush.
Why December still matters
Late-year information can clarify annual gains, income, deductions, and estimated-tax needs. A year-round process does not eliminate the year-end review; it makes that review the final checkpoint instead of the first look.
A practical cadence
- Reconcile carryovers after filing the prior return.
- Review realized transactions and estimated taxes midyear.
- Revisit after major market or business events.
- Perform a fall tax projection.
- Run a final year-end wash-sale and reporting check.
Primary sources
Important: This article is general education, not individualized tax, legal, or investment advice. Federal and state treatment depends on the facts and jurisdiction.