Semler Scientific (SMLR), a medical-device manufacturer, saw its stock drop by 15% after hours on Thursday following the announcement that the company plans to raise $75 million through a convertible senior notes offering, part of which will be used to increase its bitcoin (BTC) holdings.

The company’s stock price fell to a low of $51, and pre-market trading showed an 8% decline. Semler, headquartered in Santa Clara, California, later increased the offering size to $85 million, with an additional $15 million available via an over-allotment option. The notes, set to mature in 2030, carry an annual interest rate of 4.25%.

The conversion price for the notes has been set at $76.44, a 2% premium over Thursday’s closing price. The notes are callable after August 2028, contingent on the stock price reaching 130% of the conversion price.

Of the funds raised, $6.6 million will be used to fund capped-call transactions aimed at minimizing dilution for current shareholders, while the remainder will be directed towards acquiring more bitcoin and for general corporate use.

Semler Scientific also reported solid fourth-quarter financial results, with a 3.3% increase in revenue to $12.5 million and a rise in operating income by 8.8% to $3.7 million. The company’s bitcoin holdings have seen an unrealized gain of approximately $29 million. As of January 17, Semler holds 2,321 BTC, with an aggregate purchase price of $191.9 million and an average price of $82,689.