"How will a case that has been sealed and the fact that there was an arrest (with ACD) going to impact future employment opportunities specifically in NY in he investment banks and private equity?"
It is entirely up to the employer but in this economy more than likely with the high number of candidates seeking jobs they will pass over a candidate with an arrest record for one with out one, especially in the financial sector. If the job requires bonding then you won't get the job because more than likely they will be unable to bond you with an arrest record.
"After the case is sealed after a wait period of 6 months, can teh employer find out through background check that I was arrested and more about my case? Can I "legally" say I was never arrested if the case is sealed?"
Yes, the arrest record is permanent. The conviction is the only thing that is sealed, however in the internet era nothing is ever permanently erased so they could still find the conviction depending upon how the background check is done. You can not say you were never arrested legally. That would be lying and grounds for dismissal.
"I see 100s of background check agencies, is there anyway to find out which agency a prospective emplyer will use so the check might be done beforehand?"
You can ask them but they are not obligated to tell you.
"Is there any rule that governs these background check agencies, what if they report arrests?"
State law governs. They report what the employer hires them to find out. If they employer wants to know if a prospective employee has an arrest record then that is included.
"What if they provide data even after the case is concealed to the prospective employer?"
As long as the information they give to the employer is factual they are most likely immune from a law suit.
