Venture stage start-up Zero Financial has partnered with WebBank to issue Zerocard World Mastercard credit cards. Zerocard is available in four tiers—Carbon, Magnesium, Graphite, and Quartz. Carbon customers earn 3.0% cash back on purchases and additional rewards of 1.75% annually on average net balances if they connect automatic payment in full monthly for all charges from a Zero checking account. Magnesium, Graphite, and Quartz cardholders earn 2.0%, 1.5%, and 1.0% cash back on purchases as well as additional rewards of 1.0%, 0.5%, and 0.0% annually on average net balances. All Zerocard...