Thailand's rising public debt poses systemic risks to investment portfolios beyond direct government bond exposure. The article identifies five transmission channels: rising bond yields compress valuations of interest-rate-sensitive stocks; higher government borrowing costs force corporates to refinance at higher rates, pressuring earnings and cash flow; fiscal constraints reduce economic stimulus and public spending; capital outflows weaken the baht; and bond volatility cascades through banking and fund valuations. SMEs with leveraged balance sheets or revenue dependent on public spending face elevated refinancing and demand risks.