swvxx... money markets are just like a mutual fund, they are not insured like a bank, so I was aware of that. There is no guarantee they stay at par ($1.00) since they hold govt securities and commercial paper. However, since the yields on short term govt securities are at or above the swvxx yield, I think I am i fine but who knows.
Also, I don't have quite so much in SWVXX. I have moved a lot into very short term insured CD's and very short term govt treasuries.
The last time any MM's broke below $1 was 2008. And I was in one of the maybe three MM funds that broke below (the 'Reserve Fund, managed buy the guy who invented MM funds). It was pretty funky... it was the TDA sweep fund for their better clients. The yield was well above what treasuries were paying, so I shoulda knows there was risk. I actually took most of my money out of the market before the worst part of the 2008 fall, and stuck it all in that Money Market fund, which was hit b/c it had some Lehman paper.
That was funky. TD in essence froze the vast majority of my account. As more info came in on how much the Reserve Fund was valued at (by a government audit), they released tranches of the money over time... like every few months. Eventually they gave it all back, and covered themselves the amount it fell below par, which was in the end less than 1%.
But during the first month when they froze the Reserve fund, they would give pretty varying estimates of how much may be in the fund.... like they were saying 93% at first, then it kept on rising over time.
best.