why did I extract "New" instead of "New York"?

Can't tell because you don't actually show the code that generated the result you claim. The regex works as you seem to expect for me:

use strict;
use warnings;

my $str = <<STR;
 ended June 30, 2001 in conformity with accounting principles generall
+y accepted
in the United States of America. Also in our opinion, the related fina
+ncial
statement schedule, when considered in relation to the basic consolida
+ted
financial statements taken as a whole, presents fairly, in all materia
+l
respects, the information set forth therein.

Melville, New York                            /s/KPMG LLP
September 26, 2001
STR

my @matches = $str =~ /^\s*(\w+),\s*(\w+ \w+)(.+?\s*LLP)$/m;

print ">$_<\n" for @matches;
[download]

Prints:

>Melville<
>New York<
>                            /s/KPMG LLP<
[download]

Yes, you are right. This code works now. But when I was trying to generalize this regex, it failed. Here is the new code:

=~ /^\s*(\w+|\w+ \w+|\w+ \w+ \w+),\s*(\w+|\w+ \w+|\w+ \w+ \w+)(.+?\s*L
+LP)$/m;
[download]