Do you need an LLC for a marketing agency?
Legally, no ā you can operate as a sole proprietor in most US states. Practically, yes ā most professional US marketing agencies operate as LLCs (or S-corps at larger scale) to separate personal and business liability, simplify client contracting, and enable tax elections that reduce self-employment burden. Total setup is typically $100ā$500 depending on state; the bigger investment is a competent CPA for the first year.
Why this matters
This question shows up regularly in Google's People Also Ask for the "marketing agency" query, which is a signal that buyers in this space are asking it constantly during their research phase. The answer above is written from The Wall's editorial position ā we index 2,286 verified US growth-services vendors across 10 pillars and see how these questions map to actual buying decisions.
If you're evaluating vendors in this category, the Marketing pillar page has the full US firm list with rates, team sizes, and headquarters filters.