TP ICAP, the world’s largest inter-dealer broker, has started offering clients services in crypto-linked exchange-traded products (ETPs) in another sign of the growing mainstream adoption of digital assets.

The firm, which facilitates transactions between investment banks, hedge funds and other large financial institutions, has been trading in Europe for clients such as Goldman Sachs, Flow Traders and Jane Street, TP ICAP digital assets’ co-heads Simon Forster and Duncan Trenholme told CoinDesk in an interview.

Trading an equity-linked product on an exchange is probably the easiest way for clients to get comfortable with digital assets, Forster said, adding that the firm had been active in trading ETPs such as ETC Group’s physical bitcoin product, BTCE.

The broker is responding to increased demand for digital assets from institutional clients, and it’s not alone. UBS, Goldman Sachs and Bank of America are all clearing and settling cryptocurrency ETPs for hedge-fund clients in Europe, as reported by CoinDesk.

ETPs allow firms to gain exposure to parts of the crypto universe without investing directly. Instead the investment is through a security that tracks the performance of various digital assets.

The liquidity in some of these ETP products is “relatively modest” at present, Forster said. He expects that as more institutional money moves into the space, the number of products will grow and the overall market will expand.

Read more: Goldman Sachs Settling Crypto ETPs in Europe: Sources

TP ICAP plans to launch the trading of crypto-linked ETPs in the U.S. in the coming months, the broker said. Still, the focus for 2022 is on the roll-out of over-the-counter (OTC) derivative products based on digital assets. An OTC derivative is a financial contract that is arranged off exchange, such as a swap.

Last September, the International Swaps and Derivatives Association (ISDA), said it established a new digital asset legal and documentation working group to start looking at standards for crypto OTC derivatives.

In June last year, TP ICAP announced it was launching a wholesale trading platform for crypto assets in a joint venture with Fidelity Digital Assets, Zodia Custody and Flow Traders.