421a with very high legal rent?

Yes. Once the abatement ends they can jack the rent up.

I could be wrong but it sounds like $4,400 is market rent. So whether abatement expires or not, rent can be increased as much as the market will bear up to the legal regulated rent at the time.

AuntLydia1212,
You are essentially correct: the guidelines for rent increases every year effect the registered rent, not the preferential rent.
As far as 421a, it's a program to incentivise developers to build. In return, they have to agree to accept Rent Stabilization for as long as they are receiving tax benefits. However, if you do an internet search you will see plenty of articles where owners are being accused/sued for shady practices around this.

Yes, they absolutely plan to increase the preferential rent as much as they want; it's not capped in any way.

Insane and disgusting.

I can't believe they were given the tax break AND allowed to set the regulated rent at some sky-high number, which has reached $9k at this point.