A negative rate bond or CD is not fundamentally different from a normal one, you pay a set amount now and in the future you get a guaranteed payout at a future

A negative rate bond or CD is not fundamentally different from a normal one, you pay a set amount now and in the future you get a guaranteed payout at a future date. Except that instead of making money on the interest, you pay a little. The banks offer these products because they still make money on the fees, and on the arbitrage from loaning out the invested funds at a higher rate(or by doing nothing with a negative rate), or by bundling and selling the securities. This can still be a good option for buyers compared to investing in junk bonds or CDs that pay higher rates, or in stocks and mutual funds because what is important is the risk adjusted return and not just the yield. There are costs/risks associated with keeping a pile of cash in a vault or stuffed in a mattress, or sitting in another type of account that is not insured. If you expect interest rates to decrease even more buying a bond or CD can make money because you can sell it for more in the future, even with a negative rate. The big one is that in certain cases there are requirements to purchase CDs or treasury bonds by law, or as part of a contract, or by the governing docs of a company instead of just holding "cash". For an individual, you would be unlikely to purchase these because the cost/risk of holding cash in a bank account is minimal and some type of insurance likely covers it, and most individuals want higher returns and would rather invest in index or mutual funds than CDs even if they had positive returns. And if you think that interest rates will drop in the future and you can sell the bond for more, you are still more likely to buy higher yield bonds with higher risk.