Dear Startup Investor, Our portfolio holding Magnises is a credit card company. It also serves as a sort of club for millennials. And, much like an American Express card, it offers perks to its members. You can think of it as the American Express card for millennials… but clubbier. For example, it has a deluxe townhouse in Manhattan where members hang out. We recommended Magnises to you in June 2014. At the time, they were operating just in New…