As for money markets, don’t those get invested in treasury bills/notes anyway? Why go through a “middleman” when one has enough volume to invest directly?
Short-term obligations may not provide the yield that their financial structure requires.
10-year notes, in certain situations, provide an optimal combo of yield and risk. Provided, of course, that nothing major happens to the economy which wasn’t the case here. Then again, who’s good at predicting that?
In the end, it seemed like, given what was true at the time the decision was made, SVB made a rational choice.
There is no reason to lock money in 10 year notes, it can stay as cash or go to money market or short term obligations.