Bill Ackman’s Pershing Square International is up 23% through June 13 compared to 9.3% gains for all of last year, report Katherine Burton and Kelly Bit in today’s Bloomberg Brief, citing an unnamed source who is familiar with the hedge fund’s performance. This means that Pershing Square is on track to beat its already strong first quarter results, despite difficult trading conditions in recent months. Pershing Square was up 11.10% through the end of March, making it the sixth best performing investment fund behind Cumulus Energy Fund, Tyrus Capital Opportunities Fund, Tyrus Capital Event Fund, Merchant Commodity Fund, and Passport…