Paul Chou was among the many bitcoin aficionados who thought big Wall Street institutions were about to become heavy hitters in the cryptocurrency markets.

Chou came from one of those institutions, Goldman Sachs, and created a cryptocurrency exchange, LedgerX, that would cater to big investors with sophisticated financial contracts.

Now, in the wake of last year’s bitcoin crash, Chou is being forced to confront how few of the big finance companies acted on their cryptocurrency plans.

“It was definitely part of the original plan that institutions would be a big part of this market,” he said. “We were wrong.”

Goldman Sachs said it was opening a bitcoin trading operation to serve clients. A year later, customer interest has been weak, and the bank has not received regulatory approval to buy and hold actual bitcoins for customers, according to a person familiar with the operation, who was not authorized to comment on it publicly and spoke on the condition of anonymity.

The parent company of the New York Stock Exchange has been forced to delay the opening of the cryptocurrency exchange it announced last year and there is still no clear sign of when it will get the approval needed from regulators. The exchange declined to comment.

And the Chicago Board Options Exchange said last month that it was going to stop offering a bitcoin trading contract that it started with great fanfare in late 2017.

The faltering efforts among big financial outfits are part of a retrenchment in the cryptocurrency industry after last year’s bust, when the price of a single bitcoin fell from nearly $20,000 to around $4,000. It has lingered there for months, but had an unexpected jolt Tuesday, briefly exceeding $5,000.

Some cryptocurrency enthusiasts had hoped that the entrance of Wall Street institutions would give them legitimacy with traditional investors. But their struggles — and waning interest — illustrate the difficulty in bringing bitcoin from the fringes of the internet into the mainstream financial world.

“The smart money knows that crypto is not ready,” said Ciaran Murray, a cryptocurrency trader in London.

Murray tried to set up a hedge fund focused on digital tokens, but he found that when investors dug into the technology they were turned off.

“Once you get into the details, it scared them off,” he said.

Murray and other cryptocurrency believers are adamant that the problems are not a death blow for bitcoin and the technology it introduced. Chou, for example, is retooling LedgerX and applying for regulatory approval to open trading to small retail investors, whose interest in cryptocurrencies has held up a bit more.

And the big companies have not entirely walked away. Goldman and the parent company of the New York Stock Exchange, the Intercontinental Exchange, are moving ahead with their cryptocurrency trading operations despite tepid interest from customers. And giant asset manager Fidelity recently began working with a small number of big clients that want to hold cryptocurrencies.

Jack Dorsey, CEO of Twitter and online payments company Square, both in San Francisco, announced last month that he was looking to hire three or four bitcoin developers. He compared the technology to the early internet, both in its problems and its potential.

Even in this “crypto winter,” as some are calling it, the depressed price of bitcoin is still four times higher than it was at a peak in 2013, before an earlier crash.

But few of the more practical ambitions for bitcoin and other cryptocurrencies have been realized, and it can still be hard to determine what is real and what is not real around digital tokens.

An American company looking to set up bitcoin investment funds, Bitwise Asset Management, recently said it had determined that 95 percent of the trading activity reported by bitcoin exchanges around the world was fake.

The structure of bitcoin makes it hard to maintain control. All bitcoins are accounted for on a decentralized ledger, known as the blockchain, which no single institution controls. Anyone can have access to it, giving free rein to bad actors.

Regulators have not approved investment products tied to bitcoin because of the likelihood that prices are being manipulated. But exchanges where investors can bet on the price movement of bitcoin through futures contracts, without having to hold bitcoins, have gained approval.

The Chicago Mercantile Exchange has introduced a bitcoin futures contract that has gained moderate traction with traders. Still, the market has been small enough that the exchange’s competitor, the Chicago Board Options Exchange, said recently that it would stop issuing its own bitcoin futures contract.

Many market watchers have said that for bitcoin to gain greater favor among big investors, those investors will have to be able to buy and hold actual bitcoins.

Nathaniel Popper is a New York Times writer.