In most countries, life and non-life insurers are subject to different regulatory regimes and different tax and accounting rules. The main reason for the distinction between the two types of company is that life, annuity, and pension business is very long-term in nature — coverage for life assurance or a pension can cover risks over many decades. By contrast, non-life insurance cover usually covers a shorter period, such as one year.
In the United States, standard line insurance companies are your "main stream" insurers. These are the companies that typically insure your auto, home or business. They use pattern or "cookie-cutter" policies without variation from one person to the next. They usually have lower premiums than excess lines and can sell directly to individuals. They are regulated by state laws that can restrict the amount they can charge for insurance policies.