MicroStrategy shares jumped more than 8% on Friday after founder Michael Saylor said the company purchased another $1.1 billion worth of bitcoin.

The stock jumped 24% for the week and is now up 124% this year.

Saylor said in a post on X that MicroStrategy’s average purchase price in the four years it’s been buying bitcoin is $38,585 per coin. Bitcoin is currently trading at close to $60,000.

MicroStrategy’s stash of 244,800 bitcoins is worth $14.6 billion.

Founded in 1989, MicroStategy has a business in enterprise software and cloud-based services, but its value is now almost entirely tied to its bitcoin ownership, effectively making the company a proxy for the world’s biggest cryptocurrency. It’s the biggest corporate holder of the asset, according to BitcoinTreasuries.

In Saylor’s Friday post, he added that the “BTC yield,” a metric introduced by MicroStrategy, is 17% for the year. The number suggests that the company has created 17% more value for shareholders by selling stock to buy bitcoin.

“We’re basically giving people different types of bitcoin exposure,” Saylor told CNBC in an interview this week. “MicroStrategy’s mission is to securitize bitcoin and serve as the institutional bridge between traditional, mainstream investors and bitcoin.”

Even after this week’s rally, MicroStrategy shares are about 26% off their March high. The stock closed Friday at $141.47.

But MicroStrategy is far outperforming bitcoin, which is up 35% for the year. Saylor said owning MicroStrategy is a way to invest in bitcoin but with a variety of attributes, such as increased leverage or downside protection.

“A lot of people, they don’t want to own or they can’t own bitcoin,” Saylor said. Some would say, “Give me the volatility of the S&P and half of the performance of bitcoin, and I’d be totally happy,” he said.