Wikipedia
Sukuk (, plural of صك Sakk, "legal instrument, deed, check") is the Arabic name for financial certificates, but commonly referred to as " sharia compliant" bonds. Sukuk are defined by the AAOIFI ( Accounting and Auditing Organization for Islamic Financial Institutions) as "securities of equal denomination representing individual ownership interests in a portfolio of eligible existing or future assets." The Fiqh academy of the OIC legitimized the use of sukuk in February 1988 Since fixed-income, interest-bearing bonds are not permissible in Sharia or Islamic law, Sukuk securities are structured to comply by not paying interest. This is generally done by involving a tangible asset in the investment. For example, by giving partial ownership of a property built by the investment company to the bond owners who collect the profit as rent, which is allowed under Islamic law. Upon expiration of the Sukuk, the rent payments cease.
According to the Thomson Reuters State of the Global Islamic Economy Report 2015/16, there was $295bn of sukuk outstanding as of the end of 2014. According to the same report from Thomson Reuters, $1.814 trillion of assets are being managed in a sharia compliant manner as of 2014, which the report said had the potential to rise to $3.247 trillion by 2020.
In common usage outside of Arabic-speaking countries, the word "sukuk" is often used both as singular as well as plural. (In proper Arabic, "sukuk" is plural, "sakk" is singular.) Use of the word "sukuks" when referring to more than one Islamic bond is incorrect.