I am planning to sign up for a whole round of as many no fee cards as I can to let them season for tradelines. I also want to request a credit increase on my citi card (I inquired about moving some credit limit from one card to another, but citi said they don't do that and I have to request an increase for a specific card).
I've applied for 2 cards simultaneously by having both applications open in separate tabs and submitting them within seconds of each other. Will this same technique work for up to 4-5 different cards? Should I request a credit increase on my citi before or after this round of applications, or is it not advisable to attempt both in such a short time period?
It's possible that will work.
About 10 years ago, there was a technique called "App-O-Rama", where people applied for many credit cards in a single day. The theory was that the credit card companies couldn't see the apps in real time, and thus their application computers would evaluate each of the, say, 25 applications independently, being (un)blissfully unaware of the others. It seemed as though their information about applications was only updated on a daily (nightly?) basis. The AOR strategy tended to work really well.
Nowadays, it seems as though the information sharing is closer to real time, although it is plausible that it depends on the issuer - smaller issuers might not have done the IT and programming work. The AOR strategy works less well now, although I still lean towards it for nostalgia as well as some practical reasons.
Even so, with an 830 credit score and a 30+ year credit history and no recent credit inquiries, I applied for 15 credit cards in a single evening (not nearly simultaneously, but I had the app links ready and just went through and did them sequentially). I was approved for 10 and declined for 5. This was about a year and a half ago - I was doing this sort of thing annually and just haven't gotten around to my ninth round this year due to other things going on in my life.
The current credit climate seems to be constricting, so regardless of your personal profile, you may be declined for that reason, or you may be given a card but with a low limit.
Based on all the above, and assuming you have a good credit score and good income, I think you could easily do 4 or 5 applications semi-simultaneously with good results. Obviously YMMV.
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As far as the CL increase goes, before or after both work. It really depends on the relative value you place on the potentially higher CL with Citi vs. the new credit cards you want to apply for. I used to do it after, because I was prioritizing things like sign up bonuses and, further back in time, 0% for a year offers. Now, with piggybacking being a thing, the balance is probably shifted more towards cultivating existing lines.
I think I would probably look at my existing CL with Citi and it's age and compare those with the CL and income tiers at the piggybacking company you've got it registered with. If I thought it was likely I could get it into the next income tier and it was already old enough to get whatever I considered to be decent commissions, I'd probably do the Citi CL first.
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Whether doing both the apps and CL increase or just one or the other depends on your appetite for risk. If you need pristine credit for a new home or car or a job application, or you're nervous, then hold off. If you're a "gotta break a few eggs to make an omelet" kind of person, then consider both.