A law firm is a business entity formed by one or more lawyers to engage in the practice of law. The primary service provided by a law firm is to advise clients (individuals or corporations) about their legal rights and responsibilities, and to represent their clients in civil or criminal cases, business transactions and other matters in which legal assistance is sought.

Arrangements

Law firms are organized in a variety of ways, depending on the jurisdiction in which the firm practices. Common arrangements include:

• Sole proprietorship, in which the attorney is the law firm and is responsible for all profit, loss and liability;
• General partnership, in which all of the attorneys in the firm equally share ownership and liability;
• Professional corporations, which issue stock to the attorneys in a fashion similar to that of a business corporation;
• Limited liability company, in which the attorney-owners are called "members" but are not directly liable to third party creditors of the law firm;
• Professional association, which operates similarly to a professional corporation or a limited liability company;
• Limited liability partnership (LLP), in which the attorney-owners are partners with one another, but no partner is liable to any creditor of the law firm nor is any partner liable for any negligence on the part of any other partner. The LLP is taxed as a partnership while enjoying the liability protection of a corporation.

Restrictions on ownership interests

In many countries, including the United States and the United Kingdom, there is a rule that only lawyers may have an ownership interest in, or be managers of, a law firm. Thus, law firms cannot quickly raise capital through initial public offerings on the stock market, like most corporations. In the United States this rule is promulgated by the American Bar Association and is adhered to in all U.S. jurisdictions. The U.K. has a similar rule, but in recent years there have been discussions about relaxing it in order to allow law firms to expand more rapidly.

The rule was created in order to prevent conflicts of interest. In the adversarial system of justice, a lawyer has a duty to be a zealous and loyal advocate on behalf of the client, and also has a duty to not bill the client excessively. Also, as an officer of the court, a lawyer has a duty to be honest and to not file frivolous cases or raise frivolous defenses. A lawyer working as a shareholder-employee of a publicly traded law firm would be strongly tempted to evaluate decisions in terms of their effect on the stock price and the shareholders, which would directly conflict with the lawyer's duties to the client and to the courts.

Partnership

Law firms are typically organized around partners, who are joint owners and business directors of the legal operation; associates, who are employees of the firm with the prospect of becoming partners; and a variety of staff employees, providing paralegal, clerical, and other support services. An associate may have to wait as long as 9 years before the decision is made as to whether the associate "makes partner". Many law firms have an "up or out policy" (pioneered around 1900 by partner Paul Cravath of Cravath, Swaine & Moore): associates who do not make partner are required to resign, either to join another firm, go it alone as a solo practitioner, go to work in-house in a corporate legal department, or change professions (burnout rates are very high in law).