Entity selection is a decision, not a form.

The entity is the easy part. The structure is the work.

Anyone can file Articles of Organization with the Illinois Secretary of State and obtain an EIN. That filing creates a shell. What actually governs your business — who controls it, how profits are split, what happens when an owner leaves or dies, how new capital comes in — lives in documents almost no one reads carefully at the start. I treat formation as architecture: the entity is the foundation, but the operating agreement, bylaws, or partnership agreement are the load-bearing walls. Getting the entity right and the governance wrong is the most common, and most expensive, formation mistake I am later asked to fix.

The real entity-selection variables

The choice among an LLC, an S-corporation, a C-corporation, a professional corporation (PC or PLLC), and a partnership turns on a handful of variables that interact. Tax treatment: pass-through versus entity-level, and whether an S-election produces meaningful payroll-tax savings at your income. Liability: the protection each form offers, and how easily it is pierced when formalities are ignored. Capital: whether you intend to raise outside money, and what investors will expect to see. Control: how decision-making is allocated among owners. Exit: whether you plan to sell, bring in partners, or pass the business to family. A structure that is perfect for a single-owner consultancy is wrong for a company that will take on investors in two years — which is why the decision should be made with the next stage in view, not just the current one.

LLC, S-corp, C-corp, PC — what each is actually for

An LLC with pass-through taxation is the flexible default for most closely held Illinois businesses: simple, adaptable, strong liability protection when maintained properly, with management that can be member-managed or manager-managed independent of ownership percentages. An S-corporation is a tax election, not a separate entity — it can apply to a corporation or an LLC and may reduce self-employment tax above certain income levels, but it carries strict limits: no more than 100 shareholders, all U.S. citizens or residents, and a single class of stock. A C-corporation is usually the right answer only when you intend to raise venture capital or issue multiple share classes; it accepts double taxation in exchange for the structure institutional investors require. The C-corporation is also the only entity whose stock can qualify as Qualified Small Business Stock (QSBS) under Section 1202 of the federal tax code — a benefit that can let a noncorporate shareholder exclude a substantial portion, and in some cases all, of the capital gain on a later sale of the stock, subject to holding-period, company-size, and qualifying-business requirements that should be confirmed with current tax counsel before relying on them. For a company that may eventually be sold, designing for QSBS at formation is far easier than retrofitting it before an exit. A professional corporation or PLLC is mandatory for many licensed Illinois professions and must satisfy both the corporate statute and the relevant licensing board.

The Illinois series LLC: powerful, and easy to get wrong

For owners holding multiple properties or distinct lines of business, the Illinois series LLC lets a master entity create individually insulated sub-series, segregating the liabilities of one series from the assets of the others under a single filing. It avoids the cost of maintaining many separate entities. But the insulation is conditional: each series must keep separate records, separate bank accounts, its own documentation, and must contract in its own series name. Commingle funds or sign in the wrong name, and the liability separation degrades — exposing the whole structure. A series LLC done casually offers a false sense of protection, which is worse than none. One tax point worth understanding for any LLC: by default, an LLC with a single owner is treated by the IRS as a “disregarded entity,” meaning it is not taxed as a separate business at all — its income and expenses flow onto the owner's individual Form 1040 (typically Schedule C), unless the owner elects corporate or S-corporation treatment. The liability shield remains intact; it is only the tax treatment that passes through to the individual.

The Illinois-specific traps and federal BOI reporting

Illinois has requirements out-of-state templates miss: registered-agent obligations (a physical Illinois address, not a P.O. box), annual report deadlines and fees, assumed-name rules, and franchise-tax considerations for corporations. Federal beneficial-ownership (BOI) reporting under the Corporate Transparency Act has added a compliance layer with real penalties, and the rules have shifted — so current verification is essential before relying on any particular requirement. A formation that ignores these is not finished; it is merely begun.

Where my background changes the work

I have served as a chief legal officer and as in-house counsel to private-equity-backed companies, and I handle every formation personally. That means your entity is built by someone who has sat on the other side of the table during financings, acquisitions, and disputes, and who knows which formation decisions come back to matter years later — at the audit, the raise, or the exit. I have formed and represented numerous businesses across their full life cycle, from inception through mergers and acquisitions, which is precisely the arc a sound formation should anticipate. The goal is not just a compliant entity today; it is a structure that does not have to be unwound the first time something important happens.

What usually goes wrong

The most common failure is the off-the-shelf LLC with a boilerplate operating agreement nobody customized. It works until there is a second owner, an investor, a death, or a dispute — and then the document is silent or wrong on the exact question that matters. The second is the entity chosen for a tax benefit the owner does not actually qualify for, creating administrative cost for savings that never arrive. The third is the right entity formed and then operated carelessly — personal and business funds commingled, formalities ignored — which is precisely what opposing counsel uses to pierce the corporate veil and reach personal assets.

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