For the time deposit in the bank, the bank is in effect the "debtor". For the SDA, the bank serves as the agent and the "debtor" is the Philippine government. So, para syang bonds in a way but it's shorter term. The bank teller told me that the central bank guarantees the SDA. This makes it a very safe investment in general, the question lang is if the bank you're investing w/ is trustworthy... so siguro kung BPI ok lang, pero kung rural bank na hindi kilala yung nagooffer ng SDA baka magpa-pass na lang muna ako.
Hindi ko sure kung alin yung technically mas safe, although I think w/ both, they're both in the very safe category. Sa time deposit, I guess kausap mo directly yung bank, so that's a point for safety. You can also cancel the time deposit anytime pero may penalty. Sa SDA kasi ang alam ko pino-pool ng bank yung mga investments sa SDA so mas indirect sya. Hindi mo rin sya pwede ipre-terminate. However, based on the nature of SDAs - short term debt, government backed - safe na safe parin.