The company, the US's #1 discount party goods chain, has about 600 company-owned and franchised stores in the US and Puerto Rico. Party City sells party supplies for birthdays, weddings and bridal showers, baby showers, and a slew of holiday events -- including Halloween, its biggest season, accounting for about 20% of annual sales. Party decor maker Amscan is the chain's main supplier, furnishing about 25% of Party City's merchandise. Founded in 1986, Party City was acquired in 2005 by the principal owners of Amscan -- the private equity firms Berkshire Partners LLC and Weston Presidio -- for about $364 million.