use strict;
use warnings;

use feature qw{ say };

my $string = "{'totalResultsCount':71-24,'securityList':[{'cusip':'91%279-6.H:Y8','issueDate':'2016-06-02T00:00:00','securityType':'Bill'}";

say $1 if $string =~ m{'cusip':'([\w:%.-]+)'};
say $1 if $string =~ m{'cusip':'([^']+)};