Kushner controls hundreds of limited partnerships, each of which owns and manages a single commercial or residential property. Kushner is the general partner of each partnership and, for most, his siblings and their children are the other limited partners. These partnerships have collectively operated under the name 'Kushner Companies' (KC). KC is not a registered entity and does not own any properties. Charles and Murray Kushner accused each other of taking more than his fair share out of their common businesses. Murray alerted federal authorities to potential misconduct by his brother and KC. Kushner pled guilty in 2004 to, among other things, assisting in the filing of false partnership tax returns and federal campaign contribution offenses. The Government indicted several Stadtmauer (D), a Certified Public Accountant, a law school graduate, and Kushner's brother-in-law. He became an employee of KC in 1985 and eventually rose to become an executive vice president. D oversaw the operations of KC's residential and commercial properties. D also held a small stake (between 1% and 7%) in many of KC's partnerships. D and Kushner held equal interests (50% each) in Westminster Management, an entity which collected management fees from the other partnerships. KC employed the accounting firm of Schonbraun, Safris, McCann, Bekritsky & Company, LLC (SSMB) as its main 'outside' accountant. Bekritsky took the stand at trial. The testimony was over whether by D asking and getting an answer to whether the returns were ok to sign, what D meant by such a statement. P wanted to infer and elicit testimony from Berkritsky that the returns had known errors in them and even though fraudulent, P would not catch them. The argument on admission was Bekritsky understanding of what D knew or didn't know. The court stated: 'that the basis was his interpretation of a statement by D as to what D's statement meant because those words did not need interpretation to help the jury. That is different than this witness testifying about what, based on his perception, he believed P knew or didn't know, so I will allow it.' Eventually, Berkritsky testified: 'What I intended to convey was there were problems that we both knew that existed in the returns. The returns were prepared in a way that I thought that they would get by the Government and questions would not be raised.' D moved to strike or for a mistrial. They were denied. At summation P quoted Bekritsky's testimony with the goal being not to file accurate returns but to file returns that would not raise flags with P. D claims any reasonable person would have interpreted Bekritshy's testimony to mean the returns are okay to sign, meaning that they are correct. Following a two-month trial, the jury convicted D of one count of conspiracy and nine counts of aiding in the willful filing of materially false or fraudulent partnership tax returns. D appealed. D, in part, contends that the District Court admitted impermissible lay opinion testimony as to his knowledge of the falseness of the partnerships' tax returns by SSMB partner Stanley Bekritsky. D, in part, also contends that the court erred in admitting the testimony of Agent Grant as an expert and summary witness because she opined with insufficient factual or legal foundation that the returns were false and fraudulent.