1.80% is a very fair offer right now. On November 15, 2021, the 5 year Singapore Government Security (5 year bond) had a reported yield of 1.40% based on secondary market pricing.
It's hypothetically possible for Temasek to default on its debt obligations separate and apart from the Government of Singapore. They're not one and the same in credit risk terms, and that important fact is why this bond is yielding about 40 basis points higher than the comparable SGS. But a ~40 basis point spread seems very fair to me.
One thing that's frequently disappointing, again, is that Temasek doesn't seem to understand the U.S. Securities Act of 1933 even though they cite it. Temasek is correct that U.S. law prohibits marketing or advertising most "foreign" securities to U.S. investors absent some U.S. listing/offering requirements. But the U.S. Securities Act of 1933 doesn't prohibit the sale of these securities to what you might describe as incidental/accidental U.S. investors. If someone with a DBS account who happens to be a U.S. person presses the same buttons on an ATM (or mobile banking app) to buy this bond despite a message from Temasek that "this bond is not intended for and not marketed to U.S. persons," that's OK, that's legal. You can't solicit U.S. retail investors, or advertise to U.S. retail investors -- you can't grab them by the collar in any way -- but it's perfectly OK if they come to you and buy your bond, unsolicited/unmarketed. If for example a Singaporean wife tells her American wife, "Hey, you should buy this bond too" (word of mouth) that's legal.
Anyway, there are a lot of mythologies about U.S. personhood including this one, even among entities that supposedly should know better. It's frustrating.
