You see, we've had those funds in a money market fund, and over the years they've gone from T-bills to equally secure things, such as very secure bank notes. She doesn't ask us when she does that. I know she assumed they were very safe, because she herself has her retirement savings in ABCPs.
We also have other funds. They are in very conservative bonds. Whenever they mature, she will phone us up and we will converse either by e-mail or by phone.