MGS switch auction involves the Government buying back or redeeming certain predetermined MGS (i.e. repurchase bond) that tend to be illiquid, and to replace them with more liquid benchmark MGS (i.e. replacement bond). The main objective of the switch auction is to enable the Government to consistently issue new MGS in all market conditions, including periods of fiscal balances or surpluses. It also provides more flexibility to the Government to manage its liability through the re-profiling of debt. At the same time, switch auctions could also be used to cater investors' demand for securities of certain duration.

Participation in a switch auction is voluntary. A switch auction will be announced in advance, at least one week prior to the actual issuance date. Replacement bonds only consist of existing re-opened stocks, as new issues are unlikely to be issued via this mechanism. The list of 'off-the-run' securities that market participants may offer as repurchase bonds as well as the yields of the replacement bond will be announced to the market prior to tender closing. Interested bidders are then required to submit their respective offer amounts of the repurchase bonds as well as their respective yield valuations via Fully Automated System for Issuing/Tendering (FAST). Submitted offers would be compared against the Central Bank's internally constructed fair-valuation yield curve, which then determines the level and amount of offered bonds that are successful. The switch auction follows a variable-rate multiple-price relative-value auction format.

The switch auction could either be conducted using the duration-neutral, cash proceeds neutral or matched nominal amount method. Currently, under the duration-neutral method, the amount of replacement MGS issued and allocated to successful offers would be rounded to the nearest RM5 million which is the standard lot for MGS trading. Due to the rounding process, any remaining difference between the total proceeds of the repurchase securities and replacement securities in the switch will need to be paid either by the bidders or the Government.