my @problems;

sub required {
   my ($val, $msg) = @_;
   if ($val) {
      return 1;
   } else {
      push @problems, $msg;
      return 0;
   }
}

for my $row (@$data) {
   my ($cusip, $isin, $sedol, $ticker) = @$row;
   required($cusip, "Missing cusip for $ticker") or next;
   required($isin,  "Missing isin for $ticker")  or next;
   required($sedol, "Missing sedol for $ticker") or next;
}