The 2/3/4 rule for credit cards is a Bank of America guideline that limits how many new credit cards you can be approved for within specific time-frames.
For example under the 2/3/4 rule for credit cards you can be approved for 2 cards in 3 days, 3 cards in 12 months and 4 cards in 24 months, with the rules applying to new Bank of America accounts as well as rolling periods.
The 2/3/4 rule for credit cards is a strategy that is used to avoid too many hard inquiries on your credit and avoid risky borrower perception, which helps you manage your credit scores and increases your odds of approval, although other banks also have similar internal policies.
With the 2/3/4 rule for credit cards, you're limited to 2 new Bank of America credit card approvals within a 30 day window under the 2 in 30 days rule.
For the 3 in 12 months, you can't get more than 3 new BofA cards in a rolling 12 month period and for the 4 in 24 months you're capped at 4 new BofA cards in a 24 month period.
The 2 90 rule or 2/20 rule for credit cards is an American Express rule for credit cards that states that you can only be approved for 2 new credit cards within a 90 day time period.
And if you apply for a third American Express credit card within the 90 day time period window, that third American Express credit card application will be denied automatically.
The 9/20 rule for credit cards applies to credit cards specifically and not to charge cards or hybrid cards, like The Platinum Card or the Amex Gold Card.
However this 2/90 rule for credit cards is specific to American Express and not used by other credit card issuers that don't issue American Express cards.
The 2/90 rule for credit cards is a rule that was implemented by American Express and not a universal rule across all of the credit card issuers so you can apply for other credit cards through other credit card companies during this 90 day time period.
You're only limited to two credit card approvals through American Express, but you can apply for other credit cards such as Visa, Mastercard, Discover etc.
The third application for an American Express will be automatically denied within the 90 day period but other credit cards such as Discover, Mastercard or Visa credit cards may be approved.
Also American Express also has other application rules for credit cards, like the 1 in 5 rule that limits you to one American Express credit card approval within every 5 days.