Tax services

Small Business Taxes in Seattle, WA

Entity returns and year-round tax work for LLCs, partnerships, S-corps, and C-corps. Federal, state, and local returns prepared end-to-end — plus the planning conversations that actually lower the bill.

King County is home to a diverse range of business structures — professional-service firms, real estate holding entities, product companies with interstate sales, and contractors who cross state lines regularly. CS Precision Tax prepares entity returns for LLCs, partnerships, S-corps, and C-corps registered or operating in Seattle, Washington. Washington's economy — driven by Technology, aerospace, agriculture, shipping — generates the kinds of multi-state nexus, contract labor, and cross-border transactions that extend filing obligations well beyond a single WA return. We file Form 1065 for partnerships and multi-member LLCs, Form 1120-S for S-corps, and Form 1120 for C-corps — every required schedule, partner and shareholder K-1, and depreciation rollforward included. Washington has no state income tax. We review your full nexus footprint, file every applicable state and local return, calculate defensible reasonable compensation for WA S-corp owners, and model the net economics of an S-corp election — including payroll cost, additional bookkeeping, and the 1120-S fee — before recommending it. Local context: Technology (Amazon, Microsoft), aerospace (Boeing), no state income tax.

What to know if you file from here

Businesses in Seattle, King County should verify that WA entity filings correctly reflect nexus and apportionment, particularly for operations that serve customers outside Washington or use remote workers in other states. Washington's Technology, aerospace, agriculture, shipping industries regularly involve cross-border transactions, contract labor, and out-of-state property — each can create filing obligations beyond the WA entity return. Washington has no state income tax. Before filing Form 2553, Seattle owner-operators should model the full net savings of an S-corp election against WA payroll and compliance costs.

Who this service is for

  • Single-member LLCs and sole proprietors (Schedule C)
  • Multi-member LLCs and partnerships (Form 1065)
  • S-corp owners and pass-through entities (Form 1120-S)
  • C-corp small businesses (Form 1120)
  • Founders evaluating an S-corp election
  • Multi-state businesses and remote-employer operations
  • Real estate holding entities and short-term-rental businesses
  • Professional service firms scaling up

Typical documents we'll ask for

  • Prior-year entity and state returns
  • Year-end profit & loss and balance sheet
  • General ledger or QuickBooks Online access
  • Bank and credit-card statements for all business accounts
  • Asset purchases and sales (vehicles, equipment, property)
  • Loan documents and interest statements
  • Payroll reports (W-2s, W-3, 941s) and contractor 1099s
  • Owner contributions, distributions, and member changes
  • Operating agreement or shareholder agreement
  • Any state or city tax notices received

Frequently asked questions for Seattle, WA

Does my Seattle-based business need a separate Washington entity return?
Washington requires a WA entity return for businesses with nexus in the state. Washington has no state income tax. The state return follows the federal classification — a federal Form 1065 partnership also files a WA partnership return — but applies Washington's apportionment rules and conformity adjustments. We prepare the federal and WA returns together for clients throughout King County.
My Seattle LLC sells to customers in other states. Could I owe tax outside WA?
Possibly. Economic nexus is triggered when your sales to another state exceed that state's threshold, which can require a nonresident entity return or franchise tax filing there. Given the reach of Washington's Technology, aerospace, agriculture, shipping economy, many Seattle businesses hit out-of-state nexus thresholds earlier than expected. We review revenue by state as part of every entity engagement.

Other cities in Washington

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