HODL deposits and rewards imitate term deposits in traditional banking. The idea is that users can lock their coins in the blockchain for a set period of time and be rewarded for doing so. The rewards come from future inflation also known as the budget. HODL rewards need approval from the community just like SwiftRewards. The proposed and accepted rate within the community is 2/3rd of the minimum inflation for a 1-year deposit. For 6-months, 3-months, and 1-month deposits, the annual rate is 25%, 50%, and 75% less than the best rate. Having said that, 20% of the maximum block rewards are set aside for HODL rewards.
HODL deposits also resemble government bonds, however unlike government bonds, these deposits are not lent to any government, centralized authority or individual, but are rather locked in the blockchain and made unspendable for a set period of time. This action reduces the circulating supply for some time and should therefore, technically, boost the value of the coins in circulation during that time. It also shows long-term faith in the blockchain, which can further increase the value of all coins, both in the long-term and in the short-term. And last but not least, it can also lead to a better ROI for Staking/Mining and SwiftNodes/Masternodes.
HODL deposits are also eligible for SwiftRewards, as long as the owners make sure their address is not disqualified by turning into a zombie. This can be achieved by sending a small amount of SWIFT to the HODL address during each snapshot. HODL deposits cannot be used for staking or running a Masternode/SwiftNode. They are specifically designed for super-passive investors. HODL rewards are paid in advance upon approval and cannot be spent until maturity.