Money in the Utility Function

When we have the following utility function :

U_{t}=U_{t}(C_{t} , L_{t} , M_{t})

The first derivative to Money is higher than zero.
But what about the second derivative ??

In some utility functions in DSGE I think second derivate of money is higher than zero. I this situation what we can say about the concavity of the utility function?

Can we say this utility function is not strictly quasi concave or not ?

According to this point that second derivatives should be less than zero because utility function is strictly quasi concave.

The typical sensible assumption is decreasing marginal utility, which would imply a negative second derivative.