This is the result after the looping.

print Dumper($self);

$VAR1 = bless( {
                 'TradingStatistics::SharesOutstandingTotal' => bless(
+ {
             'SubFields::content' => undef,
             'SubFields::Description' => undef,
             'SubFields::Type' => undef,
             'SubFields::modDate' => undef
           }, 'SubFields' ),
                 'TradingStatistics::ShortInterestRatio' => bless( {
         'SubFields::content' => undef,
         'SubFields::Description' => undef,
         'SubFields::Type' => undef,
         'SubFields::modDate' => undef

         .........
[download]

Here's the tree slightly scrubed.

print Dumper($tree);

$VAR1 = {
          'TradingStatisticsIRMXL' => {
                   'TradingStatistics' => {
     'HalfYearChange' => {},
     'InstitutionsHoldingShares' => {},
     'YearChange' => {},
.....


$VAR1 = {
          'CorpMasterID' => '',
          'TradingStatisticsIRXML' => {
               'TradingStatistics' => {
     'HalfYearChange' => {
        'Description' => '26-Week Price Percent Change',
        'content' =>        ',
        'Type' => 'PriceAndVolume'   },
     'InstitutionsHoldingShares' => {
        'Description' => 'Institutions Holding Shares',
        'content' 
        'Type' => 'InstitutionalHoldings'
.....                                    },
[download]

As you can see there's a new hash inserted into the top of the tree that looks like the struct that I'm trying to build but without data, and the struct doesn't contaiin any either.

This is where I'm at a loss since my previou module is almost a duplicate except that it use a single level struct, with one loop.