Right now? treasuries. IF there is a crash, low fee index funds will destroy your account. Theres talk of Schwab struggling (dropped 20% at one point) and vanguard had questionable investments (SBNY for example). Treasuries guarantee your capital plus you earn interest. I'd look into it - TreasuryDirect is where you can get them. NFA but... its where i'm parking most of my money. Take care and good luck!