I would suppose that this would mean that there is a chance that SIA might default on its payments such that it would not be able to pay up either the principal (your original $1,000) or the coupons ($30).
But other than stable governements, most other entities all have a chance that they can't pay the bond holders up, so technically the returns from non-government entities will be not guaranteed. This should not be surprising, since every business or organisation faces some form of risk. The government theoretically faces some risk as well, but a strong government like the US, should have minimal chance of defaulting on their debt because of the strength of the US economy, and other measures that the government can take such as increasing taxes to raise capital or printing more money.
Rather than comparing what is guaranteed or not, for bonds, it would be better to look at the credit strength of the company, and pay attention to how likely the bond might be able to be repaid. Rating agencies, such as Moody's and Fitch, give credit ratings to bonds for investors to determine how likely a company will be able to pay the investors back. Since SIA's bonds were not rated, you could look at some measures that represents how credit-worthy SIA is here https://seedly.sg/questions/what-are-some-ways-...
But based upon what I have read, the credit risk of the bonds don't really justify the returns. The returns are higher than the SSBs, but only slightly. The SSBs can almost be seen as default free, where your returns are guaranteed but your SIA bonds certainly have much more risk to them.
I would suppose that this would mean that there is a chance that SIA might default on its payments such that it would not be able to pay up either the principal (your original $1,000) or the coupons ($30).
But other than stable governements, most other entities all have a chance that they can't pay the bond holders up, so technically the returns from non-government entities will be not guaranteed. This should not be surprising, since every business or organisation faces some form of risk. The government theoretically faces some risk as well, but a strong government like the US, should have minimal chance of defaulting on their debt because of the strength of the US economy, and other measures that the government can take such as increasing taxes to raise capital or printing more money.
Rather than comparing what is guaranteed or not, for bonds, it would be better to look at the credit strength of the company, and pay attention to how likely the bond might be able to be repaid. Rating agencies, such as Moody's and Fitch, give credit ratings to bonds for investors to determine how likely a company will be able to pay the investors back. Since SIA's bonds were not rated, you could look at some measures that represents how credit-worthy SIA is here https://seedly.sg/questions/what-are-some-ways-...
But based upon what I have read, the credit risk of the bonds don't really justify the returns. The returns are higher than the SSBs, but only slightly. The SSBs can almost be seen as default free, where your returns are guaranteed but your SIA bonds certainly have much more risk to them.