The BEL 20 is the benchmark stock market index of Euronext Brussels. It tracks the performance of 20 most capitalized and liquid stocks traded in Belgium. In general, the index consists of a minimum of 10 and a maximum of 20 companies traded at the Brussels Stock Exchange. Since 20 June 2011, the BEL 20 has contained 20 listings, with the exception a one-month period in May–June 2018 when Ablynx stock was removed following the takeover by Sanofi,[1] only to be replaced mid June by arGEN-X.
Rules
The composition of the BEL 20 index is reviewed annually based on closing prices on the last Friday in February.[2] These changes are effective after the third Friday of March. In addition to meeting a set of criteria demanding a company be "representative of the Belgian equity market", at least 15% of its shares must be considered free float in order to qualify for the index.[2]