Each state has laws that set out basic operating rules for LLCs, some of which will govern your business unless your operating agreement says otherwise. (These are called "default rules.")
Many states, for example, have a default rule that requires owners to divide up LLC profits and losses equally, regardless of each member's investment in the business. If you and your co-owners did not invest equal amounts in the LLC, it's doubtful you'll want to allocate profits equally. To avoid this, your operating agreement must spell out how you and your co-owners want to split profits and losses.
By writing an operating agreement, you can choose the rules that will govern your LLC's inner workings, rather than having to follow default rules that may or may not be right for your LLC. As an owner of an LLC, you are not required to take a "salary" where you would normally pay FICA and Medicare taxes on. Instead the net income of the LLC becomes subject to the same FICA and Medicare taxes up to the current limits. The net effect is the same, but by not taking a "salary" you do not have to file payroll tax reports with the IRS. get a lawyer for in-depth details.
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