When your lender trots out a great new credit card offer, you don't have to miss out. However, maintaining multiple accounts with the same bank carries a few risks that might outweigh the rewards.

Most credit card issuers actually want you to maintain more than one account with them. Increasing your credit means increasing your loyalty, which is why so many banks offer such targeted rewards credit cards. I can understand why you'd want to diversify your accounts. Citi Platinum Select Visa Card is a great balance transfer credit card, but it offers relatively few perks beyond its lengthy introductory period. Meanwhile, Citi's been loading up the two cards you mentioned with plenty of bonuses:

• Citi Dividend Platinum Select Visa Card - $100 Cash Back. This cash back credit card offers a rebate of 1 percent on your eligible purchases, plus bonuses of up to 5 percent from Citi on seasonal feature categories. In many ways, Citi has set up their Dividend brand as a head-on competitor to the Discover Card, even matching some of that card's signup bonuses.
• Citi Diamond Preferred Card. Citi's own version of the "black card" boasts its own 24/7 concierge service to help book your hotel rooms, flights and more. This premium credit card also includes membership in Citi Private Pass so you can gain access to exclusive, VIP events, reward experiences, and entertainment programs. Citi(R) Price Rewind searches for a lower price. Learn how you can get lower price after you purchase an item.

Your current credit score and risk profile may already qualify you for the Citi Diamond Preferred Card. If you are uncertain about your ability to qualify, you may benefit from being an existing customer, as Citi's algorithm may even be more forgiving of a lower credit score if they can access internal information about your income or payment history.

However, many consumers find that opening a second credit card with the same issuer often results in a lower credit limit than they expected. Each bank sets its own risk threshold, so your maximum credit line could end up diluted across multiple accounts. After you open your new credit card, talk to your lender's customer service team to see if you qualify for a re-balancing of your overall credit limit across both accounts.