I was reading some slides on high frequency data and i came across these statements: "data discreetness induces high degree of kurtosis" "Non synchronous trading and risk premium are sources (spurious) of serial correlation"

Does anyone have any comments that can enlighten my understanding ?

Many thanks

I was reading some slides on high frequency data and i came across these statements:

data discreetness induces high degree of kurtosis

and

Non synchronous trading and risk premium are sources (spurious) of serial correlation

Does anyone have any comments that can enlighten my understanding ?