You had good replies, but if i can add something, i would start with a simpler approach: a linear one, accomulating results and eventually discard them if unneeded. Consider:

use strict;
use warnings;

my $trig = 'Significant Accounting Policies';
my $res;

while (<DATA>){
    if ($_ =~/$trig/i){
      $res = $_;
      next;
    }
    $res.=$_ if $res;
}
print $res;

__DATA__
Wal-mart talks about its Significant Accounting Policies in its 10k.

Significant Accounting Policies are important for a firm.

Here is a list of the Significant Accounting Policies

1)Lifo

2)Depreciation

3)Expenses
[download]

Or a similar approach but using a pointer:

my $trig = 'Significant Accounting Policies';
my @res;
my $pointer;
while (<DATA>){
     $res[$.-1] = $_; # or just: push @res,$_;
     $pointer = $.-1 if /$trig/i;

}
print @res[ $pointer .. $#res ];
[download]

HtH
L*