I just received a CLI on my Capital One Quicksilver card from $1000 to $4000 this morning. I did not request the increase, but in the past six months I've paid off the card which used to have a balance, and over the past two to three months starting pumping transactions through the card to equal about 50% of the balance, then paid it down to $10. It is my AZEO card with a balance. I had just achieved AZEO a few weeks ago.
I decided I had to work on just increasing the credit lines on cards I have now because we are going to be building a house soon and will need no hard pulls for awhile.
Some history on this card. First acquired the card in Dec 2015 at a $300 credit line when I started to rebuild. I had a couple of credit line increases up to $1000 by about 2017. I believe it may have been a bucketed card at one point, but a few years ago they offered a product change to a Quicksilver card with no annual fee.
So it will be interesting to see if they also change the other Capital One card, which is a Quicksilver One with a $39 annual fee. Current CL on that one is $1450. This one has also not had a credit line increase since June of 2017. Same approach, I've been pumping transactions through this one also up to about half of the balance, then paying it to zero before the statement date.
Congratulations on your PCLI!
Nice, grats on the 4x increase 
Congrats on a very nice Cap1 increase!
