NASDAQNASDAQ, the world’s second-largest stock exchange, filed suit in the U.S. District Court for the Southern District of New York Thursday against a New Jersey fund management company, claiming it is attempting to steal a number of multimillion-dollar exchange-traded funds in its care.

ETF Managers Group was contracted by the stock exchange, as part of an agreement reached with a company purchased by NASDAQ in 2016, to manage the PureFunds line of ETFs, according to the complaint in NASDAQ v. ETF Managers Group, 17-cv-08252.

The complaint states that ETF Managers has operated the funds since 2015. The funds, first launched in 2012, focus on a number of areas, such as video games and cybersecurity. The latter fund has more than $1 billion in assets under management, NASDAQ claims.

According to NASDAQ, the relationship between ETF Managers and the stock exchange hit a turbulent period that culminated in a letter from ETF Managers CEO Samuel Masucci to NASDAQ and its partner in the creation of the funds, PureFunds. In it, Masucci allegedly stated that PureFunds and NASDAQ had improper communications with ETF Managers as well as outside parties, and noted a lawsuit, filed in Superior Court in New Jersey by PureFunds, that alleged similar aims by ETF Managers as the NASDAQ suit—namely, that the managers were attempting to obtain control of the funds.

Masucci told NASDAQ it was terminating its agreement to produce the profits of three of the funds to NASDAQ and PureFunds.

“The only logical conclusion that can be drawn from these actions is that defendants sought to seize control of the PureFunds ETFs and the profits they generate, and manufactured a means of achieving these goals,” the complaint stated.

Since then, ETF Managers has changed the names on the funds, removing “PureFunds” from the titles. However, the tickers associated with the funds remain the same. Of greater material consequence, according to NASDAQ, the ETF Managers hasn’t paid profits on the ETFs since March, which total more than $1.2 million.

Ballard Spahr associate Justin W. Lamson is representing NASDAQ. He referred a request for comment to a NASDAQ spokesman who declined to comment.

On top of the breach of duty claims, NASDAQ also alleges ETF Managers’ decision to switch distributors represents a breach of the wholesaling agreement, resulting in an additional $600,000 in associated fees.

A spokesman for ETF Managers could not be reached.