use HTML::Template;
my $src = q{
<h1>Stock data..</h1>
<ul>
<TMPL_LOOP STOCKLOOP>
<li><TMPL_VAR NAME> <TMPL_VAR NET></li>
</TMPL_LOOP>
};
my $tmpl = HTML::Template->new( scalarref => \$src );

my %stock = ( 'Nikkei 225' => ^N225 );
my @STOCKLOOP;
for my $name ( keys %stock ) {
  my $symbol = $stock{$name};
  my %dat = $q->fetch( $name, $symbol ... # or whatever you do to get this
  push @STOCKLOOP, { name => $name, net => $net };
}

$tmpl->param( STOCKLOOP => \@STOCKLOOP );

print "Content-Type: text/html\n\n";
print $tmpl->output;