Changes

permno-

date-

excode -

sic - letter "Z", value 711 (most are 4 digits),

ncusip -

ticker -

name -

naics -

primex -

permco -

cusip -

Price - Null values, negative numbers,

vol - null values

ret - null values, letter "B" as value multiple times, letter "C",

shout - null values

trade - null values

eqret -

vret -