Tax Preparation Services Built for Complex Returns

Here's a worked example of why withholding review matters at filing time:

By Bryan Martin, CPA, Managing Partner and Founder of Taxstra · Last reviewed July 10, 2026

Here is the short answer. A Taxstra tax preparation engagement covers your federal return plus every required state return, e-filed, with a review call before anything is submitted and workpapers retained so every figure can be defended if the IRS ever asks. It is built for people whose returns stopped being simple: equity compensation, K-1s, rental portfolios, multi-state income, and S corp or partnership ownership. Everything happens remotely through a secure client portal, so it works the same in all 50 states.

The standard behind it: every number on the return should be supportable years later without a scavenger hunt. In practice that includes:

• Individual and business return preparation. Form 1040 plus 1120-S, 1065, or 1120 as your structure requires, prepared by the same team so they reconcile.
• K-1 reconciliation and basis tracking. Basis, at-risk, and suspended loss schedules maintained year over year, not reconstructed in a panic.
• Equity compensation reporting. Basis adjustments on RSU and ESPP sales, ISO exercise tracking, and withholding review against your actual bracket.
• All required state filings. Resident, nonresident, and part-year returns with sourcing and credits handled deliberately.
• Elections review. Depreciation methods, safe harbors, grouping elections, and state pass-through entity tax coordination, applied consistently.
• Extension and payment strategy. When extending makes sense, we estimate the liability and recommend a payment so penalties stay minimal.
• Secure portal and digital workpapers. A tailored document request list, bank-level encryption, and workpapers retained to defend every figure.

Every return is prepared by a trained tax accountant and reviewed by a senior accountant against a structured checklist. Two sets of eyes is the policy, not the exception.

Fees are flat, quoted up front after a short initial consultation, and scale with complexity rather than hours. For how CPA preparation fees are typically structured, see our guide on how much a CPA costs.

Missing one or more prior-year returns is a different engagement from ordinary current-year preparation. Start with our CPA back taxes service, which coordinates multi-year filing, transcripts, and any balance-resolution work in the right order.

Most complex returns don't fail in an audit. They fail in a computer. The IRS matches every W-2, 1099, and K-1 it receives against what your return reports, and any mismatch generates an automated notice. No human required.

Once your income includes equity compensation, pass-through entities, rentals, or multiple states, the number of places a return can silently break multiplies. A generalist preparer working through a 400-return season doesn't have time to reconcile your brokerage basis or rebuild a missing K-1 basis schedule. So the error ships, and you find out eighteen months later.

If your situation crosses several of these at once, that is normal here. Most of our clients combine at least two.

Tech employees and executives with equity compensation. RSUs, ISOs, NSOs, and ESPP shares each carry their own reporting rules, and the withholding your employer applies rarely matches your actual bracket. If you want the strategy side of this, not just clean filing, our high-income tax planning guide covers the levers in depth.

Physicians, especially locum tenens and 1099. Mixed W-2/1099 income, work in four states, and quarterly estimates nobody set up correctly. This is our flagship vertical; see our physician tax services for the full picture.

Real estate investors. Depreciation schedules, passive activity loss tracking, short-term rental activity, cost segregation reporting, and K-1s from syndications. Most preparers get the depreciation wrong or lose the suspended losses. Our real estate tax services exist because of how often we have to fix this.

Business owners with S-Corps and partnerships. Books-to-return alignment, reasonable compensation documentation, accountable plans, and state apportionment, filed so the entity return and your 1040 tell the same story.

Work in two or more states and your filing question changes from "what do I owe" to "which state gets which dollars." Get the sourcing wrong and two states tax the same income; miss a credit for taxes paid to another state and you've donated money no one will ever refund voluntarily.

We handle nonresident and part-year returns, reciprocity agreements, credits for taxes paid, and the state-by-state sourcing rules that determine where wages, business income, and equity compensation are actually taxable. For locum physicians and remote employees, this is routinely the largest error in prior-year returns we review. Full detail on our multi-state filing service.

Tax preparation is backward-looking by definition. It reports decisions that have already been made. Tax planning is the forward-looking work: entity structure, retirement plan design, equity timing, real estate strategy. A correctly prepared return is the dataset every one of those decisions is built on.

Planning is Taxstra's flagship service, and preparation is engineered to feed it. Most of our preparation clients pair compliance with a tax planning engagement: the same team that prepares your return models what next year's return should look like, then helps you execute the changes while the calendar is still open.

We review every new client's prior two to three years of returns as part of onboarding. When we find errors or missed elections worth amending, we tell you, with the dollar impact, before we prepare anything new.

• CPA + MBA + licensed real estate broker. Founder Bryan Martin's credential stack means rental, STR, and cost segregation returns are filed by someone who understands the underlying transactions, not just the forms.
• Genuine multi-state expertise. Locum tenens sourcing, NY/NJ nonresident filings, and state credit coordination are daily work here, not annual novelties.
• A planning firm that files, not a filing mill that upsells. Compliance is engineered to support strategy, elections, basis, and documentation are maintained with next year in mind.
• Established and nationwide. More than 1,000 clients across all 50 states, a real firm with review processes, not a solo side practice.
• Trusted in the physician community. As featured in White Coat Investor (Podcast Episode #459).
• Tech-forward. Secure client portal, digital workpapers, modern tooling, fast turnaround.