This bill adds a new section to chapter 82.87 RCW and amends the chapter’s definitions in RCW 82.87.020. The new section lets an individual taxpayer who owes tax under chapter 82.87 submit payment beginning six months before the due date for filing and payment for that taxable year. Payments must be made in the manner and form the department prescribes. If the department determines the taxpayer overpaid for that taxable year and is entitled to a remittance, interest may not be assessed for the period before the due date. These are procedural changes to payment timing and interest assessment, not criminal or penalty escalations. The amendment to RCW 82.87.020 rewrites and clarifies many definitions used in the chapter, including a detailed definition of “adjusted capital gain” (based on federal net long-term capital gain with specified additions and subtractions), “capital asset,” “federal net long-term capital gain,” “individual,” “intangible personal property,” “long-term capital asset/gain/loss,” “real estate,” “resident” (with domicile and 183/30-day tests), “section 1256 contract,” “tangible personal property,” “taxable year,” “taxpayer,” and “Washington capital gains.” The Internal Revenue Code reference is fixed to the 1986 Code as amended through July 25, 2021, unless the department adopts a later date by rule. The text refers to other chapter provisions (RCW 82.87.060 and RCW 82.87.100) for modifications and allocation rules, but those provisions are not included in the extracted facts. The department responsible for prescribing payment form and determining overpayments is not named in these extracts, and no effective date for the changes is provided.

If enacted, individuals who owe the Washington capital gains tax could choose to pay up to six months before the tax filing due date using whatever payment methods the department requires, giving taxpayers more flexibility to prepay and possibly smooth their cash flow. If the department later determines those early payments were overpayments, it may not charge interest for the period before the original due date, so taxpayers who overpay early would likely avoid interest for that pre‑due date window. The department (responsible for prescribing payment form and handling refunds) would need to accept and process earlier payments and any resulting remittances, which could shift administrative workload and timing of cash receipts and refunds; however, the bill text here does not identify the department by name, does not show an effective date, and omits related allocation and modification details in other sections, so the exact operational and timing effects remain unclear.