The Main Market is the flagship stock exchange market of the London Stock Exchange (LSE), which provides access to the largest and most established companies in the UK and abroad. The Main Market is the oldest and most prestigious market on the LSE, dating back to 1801. It is a regulated market that is subject to strict listing requirements and rules, designed to protect investors and ensure the integrity of the market.

Companies listed on the Main Market typically have a large market capitalization and are considered to be blue-chip companies. The Main Market is split into two segments: the Premium Listing segment and the Standard Listing segment. The Premium Listing segment is the most prestigious segment and has the strictest listing requirements, while the Standard Listing segment has less stringent requirements.

To be listed on the Main Market, a company must meet certain eligibility criteria, including a minimum market capitalization and a minimum number of shares in issue. The company must also comply with the LSE's listing rules, which cover matters such as corporate governance, financial reporting, and disclosure requirements.

Once a company is listed on the Main Market, its shares can be traded by investors through a broker or other trading platform. Trading on the Main Market is conducted electronically and operates on a continuous auction basis. The market is open from 8 am to 4:30 pm on weekdays, except on bank holidays. The Main Market is subject to regulation by the UK Financial Conduct Authority (FCA) and is overseen by the LSE.