Before graduating from Yeshiva University, Ari Wallerstein had already completed four internships—at TBC Corporation, a day school, Sumitomo (TBC’s parent company), and CohnReznick. By the time he crossed the stage at graduation, he knew exactly where he was headed: a large public accounting firm.
On to the Big Four
He joined KPMG through Yeshiva’s recruiting process, working in federal tax compliance for global banking and earning a promotion to senior associate. A deepening interest in ASC 740, the accounting standard for income taxes, led him to Deloitte, where he joined their national tax accounting group focused exclusively on that work. There he developed a specialty in post-merger and acquisition restructuring, which eventually brought him to EY, where he joined the tax M&A group.
Shifting to In-House Tax
After more than five years across three of the Big Four, Wallerstein made the move in-house. In 2022, he joined Payoneer, the global digital payments platform, as one of its first two tax hires—building the tax function from scratch while gaining substantial exposure to international transfer pricing across Payoneer’s global operations.
In spring 2025, Wallerstein joined Bilt, a neighborhood rewards and loyalty platform, as its first tax hire, reporting directly to the chief financial officer. He oversees all tax matters for the company and has been a Bilt customer since 2021. “There’s something meaningful about working for a company whose product you genuinely believe in, and that goes well beyond the tax complexity it presents,” he says.
Connecting With TEI
Wallerstein joined TEI as his responsibilities at Bilt grew in scope. He was drawn to the organization’s network of in-house tax professionals at comparable career stages, peers navigating shared challenges around leadership, executive communication, and team development.
He is currently part of the second cohort of TEI’s Tax Leadership Academy. “The value is in the range of experience around the table, people who’ve taken very different paths but are wrestling with the same questions,” he says, noting that the program’s focus on leadership has been especially valuable at this point in his career.
Outside of work, Wallerstein enjoys cooking, traveling, and exploring with friends. He cooks nearly every day, and when asked about his favorite recipe, he points instead to his favorite utensil: a wok. “Even if it’s not the traditional method, I’m making it in the wok,” he says.
