Jack Dorsey, CEO and co-founder of Twitter and founder and CEO of Square, speaks at the Consensus 2018 blockchain technology conference in New York City, New York.

Square generated $37 million in revenue on bitcoin in the second quarter, but it spent almost as much to offer free trading of the volatile cryptocurrency on its Square Cash App. For now, the payments start-up says it's not relying on crypto to add to its bottom line.

"It's not a major monetization engine," Chief Financial Officer Sarah Friar said on a call with reporters after releasing second-quarter earnings Wednesday. "The goal is to continue to drive utility in the Cash App."

The payment company launched bitcoin trading in its Cash App in January. In order for customers to be able to buy and sell bitcoin instantly, Square holds a certain amount of cryptocurrency on the customer's behalf. But in the time between Square buying bitcoin and customers making a trade, the price can change drastically and the company can lose money, Friar explained.

"We have some spread in there to allow for the fact that bitcoin is volatile," she said. "We're not trying to push on the monetization of bitcoin today."

Bitcoin has lost nearly half its value this year, and the price often rises or falls by hundreds of dollars in a single day. The cryptocurrency gained attention after climbing to almost $20,000 in December.

Of Square's total $815 million net revenue, which grew 48 percent year over year, bitcoin brought in $37 million. But the company spent $36.6 million on bitcoin. In total, Square made a total $420,000 on the cryptocurrency.

"We only apply a small margin to the market cost of bitcoin when we sell bitcoin to customers, and we have no control over the cost of bitcoin in the market, which tends to be volatile," Square said in the 10-Q .

The fintech company brought in $385 million in adjusted revenue, which factored out transaction-based costs and bitcoin costs. That number was above what Wall Street analysts were expecting. The company also outperformed on EPS but came up short on EBITDA and EPS guidance analysts had expected for the third quarter.

The company, run by Twitter CEO Jack Dorsey, is best known as a credit card processor but also offers payment hardware, the peer-to-peer Cash App, and small business lending. Shares of the start-up have surged more than 140 percent in the past year and 88 percent this year alone.