I am going to answer this is a US centric way. The US is a country that doesn't require a grace period, but most credit cards do offer a grace period. There is a group of credit card users who never pay interest on their cards. They use the grace period to its fullest potential by paying the full amount of the statement balance by the exact due date. They use the card for everyday purchases and large purchases, even if there was a time that those purchases would have been done with cash or a check. They would use it to buy a car, or pay their property tax or to be honest any tax as long as there was no fee to do so. They use all these transactions to earn miles, points or cash back. If interest rates on bank accounts were non-insignificant they would also calculate the extra interest they were earning by delaying payment of large purchases for the 30 day statement length plus the 25 day grace period. Imagine a major credit card announced that the grace period would end on December 31st this year. - If they grandfathered all the account holders of record on December 31st they would see a big influx of new applications becasue they they wanted to beat the deadline. Those new card holders would be applying to make sure if this becomes the norm, they have one credit card they can use that has the grace period. - But if they announced that only current holders on the date of the announcement could keep the grace period, then new applications would decrease to near zero. Many potential customers would rate the card benefits as very poor. Some would still apply becasue the they weren't in the group of consumers that were described above. Of course current users would still use the card. - But if they announced that the 31st of December deadline ended the grace period for all accounts regardless of current status, the usage of the card would drop. People who had other cards with grace periods would shift to those other cards as their main card. Many/most would cancel the card if they thought the hit on their credit score would be survivable, or if there was a annual fee. Now if this was the beginning of a new trend, then at some point most cards would also make the change. the question would be could the early adopters survive to that point. They would have to calculate that they could survive that bold business decision, and gamble that other card companies would also make the change. If other cards didn't make the change it might take years after the the grace period was restored before they gained back those customers. Of course the credit card companies know the sources of their income: Fees, penalties, interest, transaction fee. They also know their expenses: normal business costs, defaults, fraud, and card benefits. they know how to model changes to card benefits. In the last year or two many card companies have ended or scaled back some of their other benefits: automatic extended warranties, free rental car coverage, price protection, etc. I have not heard of a large number of consumers switching cards, becasue for most consumers these were benefits that were either used infrequently, or made up only a small portion of their used benefits. the question is what benefit change will come next... ---------- regarding the requirement for a grace period in the US according to to the [Consumer Financial Protection Bureau] a part of the US government: > A grace period is the period between the end of a billing cycle and > the date your payment is due. > > During this time, you may not be charged interest as long as you pay > your balance in full by the due date. Credit card companies are not > required to give a grace period. However, most credit cards provide a > grace period on purchases. [grace]:https://www.consumerfinance.gov/ask-cfpb/what-is-a-grace-period-for-a-credit-card-en-47/