Not bad. I would change the way the keys are generated slightly, though. This change allows the data vendor to do weird things, like change the order of headers or add / remove columns without affecting your underlying process (unless they completely balls it up).

my %item_map = ( 'CO.NAME'   => 'name',
                 'MARKETCAP' => 'cap',
                 'INDUSTRY'  => 'ind' );

chomp(my $headers = <DATA>);
my @headers = map {s/\s//g; ($item_map{$_} || lc $_)} split /\s*\|\s*/
+, $headers;
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Yes, purists may point out that this is serious over-engineering. I would retort that if they had to maintain loading filesets from a couple of hundred different FTSE feeds they might rethink their position (though to be fair, FTSE are a lot better these days)