Digital Asset Holdings is proposing to build something similar to the blockchain database, in order to provide a cheaper and faster way to trade other sorts of financial assets, such as loans and foreign currencies.

The problem for Ms. Masters is that several other start-ups are trying to do something similar, and there is no guarantee that any of the start-ups will ultimately succeed. Many industry experts think that it could take years to get to the point where the blockchain technology can be used effectively by banks — if it works at all.

The New York-based start-up ItBit, which is building its own blockchain-like technology, had been out trying to raise $100 million based on the assumption that the company was worth $250 million. More recently, it has scaled that back and is now hoping to get $50 million from investors, with a valuation of $135 million.

Ms. Masters hopes to raise from $35 million to $45 million, valuing the company at $100 million.

Digital Asset Holdings is a relative newcomer to the area. It grew out of a Bitcoin trading operation created by the Chicago trading firm DRW, which operated through a little-known subsidiary of DRW known as Cumberland Mining & Materials.

The founder of DRW, Don Wilson, helped recruit Ms. Masters, 46, to Digital Asset Holdings this year. Ms. Masters, Oxford-born and Cambridge-educated, had worked at JPMorgan for nearly three decades.

She became one of the bank’s better-known employees after helping to develop the credit default swap in the 1990s. But Ms. Masters left JPMorgan in 2014 after a unit in the commodities business she headed was accused of manipulating electricity prices. Ms. Masters was not accused of wrongdoing, and the bank has said that her departure was not tied to the regulatory problems.

Soon after Ms. Masters joined Digital Asset Holdings, known as D.A., this past spring, the company began working with the investment bank Sandler O’Neill to raise money. Within the company, there was an expectation that the fund-raising would be finished by the fall, according to people briefed on the situation.