Semler Scientific (SMLR -2.31%) rose 24.5% in October, according to data from S&P Global Market Intelligence. THE medical device the company began to buy back Bitcoin with cash on its balance sheet, which correlates its stock price to the popular cryptocurrency. Even after last month’s price rally, the stock is still down 35.4% over the past five years, due to slowing revenue and declining operating margins.

Here’s why Semler Scientific stock jumped last month.

Add Bitcoin to the balance sheet

The reason Semler Scientific’s stock jumped in October has nothing to do with its underlying business. In fact, the company had no significant updates to provide to investors during the month. The only reason the stock went up is because management decided to put most of the company’s cash into Bitcoin. In October, the price of Bitcoin reached over $72,000, close to an all-time high. In its recent quarterly update, Semler Scientific told investors that it now owns 1,058 Bitcoins, which equates to a value of $76 million at a Bitcoin price of $72,000.

This currently represents a large portion of Semler Scientific’s market value. As of this writing, the company has a market capitalization of $219 million, meaning 35% of its value comes from its Bitcoin holdings. If the price of Bitcoin continues to rise, Semler’s stock will continue to rise. It’s that simple.

How is the health sector doing?

Even though Semler Scientific appears to have fallen in love with Bitcoin, the company still operates a medical device segment with its QuantaFlo product, serving the peripheral arterial disease (PAD) market. The division’s revenue over the past 12 months was $61.7 million and fell 17% year over year in the third quarter. Declining revenue is never a good thing, and this may be why Semler Scientific decided to invest in Bitcoin.

The company nevertheless still displays a positive operating result, and has done so for five years. Last quarter, operating income was positive $5.1 million and $22 million in the last 12 months.

Overall, Semler Scientific took a big risk with its business. Investing in Bitcoin can be volatile because the price can increase or decrease quickly, and there is no guarantee that the company will make money from its operations. For now, its medical devices division is generating profits, but the decline in revenue should be of great concern to shareholders. There is no reason to invest in Semler Scientific after its pivot to Bitcoin.