Costco is set to launch a new credit card that offers the best cash back rates on restaurants, travel and gas. The company's new card is under Visa management and will be unveiled in June 20 this year.

Costco's former card was previously managed by American Express. Its 16-year deal with AE just recently ended and the company promptly transferred to Visa.

This new credit card offers 4 percent cash back on gas purchases on eligible pump stations (up to $7,000 per annum, then 1 percent back), 2 percent back on Costco and Costco.com purchases, 3 percent back on travel and restaurant purchases, and 1 percent back on almost anywhere.

Existing customers of Costco need not do much of anything to get this new Costco Anywhere Visa Card. They will automatically receive their card via standard mail. But they should still use their existing American Express-backed card until June 19.

Starting on June 20, all Costco issued American Express cards will be automatically cancelled and will not be honored in any Costco stores or affiliates.

Getting the new card will have no effect on the credit scores of customers. Citigroup said it will not refer to any credit report when it transfers customers account.

Any existing rewards that customers have earned with American Express cards will not be affected. That means Costco customer will not lose these accumulated rewards, but only up to June 20.

After that deadline, all rewards will be moved to the new Visa cards together with any outstanding balances. But American Express membership benefits will not be transferred to the new cards, according to American express.

Sean McQuay, a credit-card expert connected with the NerdWallet website said that the new Visa card has some of the best rewards of any card today. It requires no annual fee, although customers have to pay $55 annual Costco membership fee to be able to use it.