LLC vs S-Corp vs Sole Proprietorship: choosing your first structure

Sole proprietorship: the default you may already be

If you sell something under your own name and never file anything, you are already a sole proprietor. There is no state entity to create, which is why it is the cheapest and fastest way to operate. If you use a business name other than your own, Illinois counties require you to register an assumed business name, but that is a registration, not a new legal entity.

The trade-off is the one that matters most: there is no legal separation between you and the business. Business debts are your debts. If the business is sued, your personal assets are in the conversation. For a low-risk side project that may be acceptable for a while. For anything with customers on premises, employees, inventory, or contracts, most founders outgrow it quickly.

LLC: separation without ceremony

A limited liability company creates a legal person that is not you. Done properly, and kept properly separate (its own bank account, its own records, no mixing of personal and business money), it puts a wall between business obligations and your personal life.

LLCs are popular with first-time founders for a reason: the formalities are light compared to a corporation, the structure flexes from one owner to many, and by default the taxes flow through to your personal return, so there is no separate corporate tax layer. In Illinois you create one by filing Articles of Organization with the Secretary of State and keeping up a modest annual report each year. The filing fees are published on the Illinois Secretary of State website; verify the current amounts there before you budget.

The S-Corp surprise: it is not actually an entity

Here is the misconception that costs founders the most confusion: an S-Corp is not a type of company you form. It is a tax election you make with the IRS on top of an existing entity, most often an LLC or a corporation. "LLC vs S-Corp" is therefore not really an either/or; many businesses are an LLC that later elects S-Corp taxation.

Why elect it? Once a business earns comfortably more than what a fair salary for the owner would be, S-Corp taxation can reduce self-employment taxes by splitting income into salary and distributions. But it brings real obligations: payroll must actually run, a reasonable salary must actually be paid, and there are eligibility rules to keep. If the numbers are small, the overhead can eat the benefit. This is exactly the kind of decision to make with an accountant, using your real projections, not a blog post.

How to actually decide

• If you are testing an idea with little risk and no name to protect: starting as a sole proprietor is legitimate; just know what it does not protect.
• If the business will have customers, contracts, inventory, or employees: an LLC is the common first move, because separation matters more than optimization at this stage.
• If profits are becoming meaningfully larger than a fair owner salary: ask an accountant whether an S-Corp election pays for its own overhead.
• Whatever you choose, keep business and personal finances strictly apart from day one. Structure only protects you if you respect it.

One honest closing note: articles like this one can map the territory, but they cannot see your situation. Structure interacts with taxes, licensing, funding plans, and even how you intend to exit. It is a one-hour conversation with the right professionals, and it is worth having before you file, not after.