KULR (KULR), a maker of advanced energy-management systems, said it spent $8 million on bitcoin (BTC) to take its total holdings to 510 tokens.

At a weighted average price of $101,695, that equates to almost 79 bitcoin and means the company’s total investment is now $50 million.

The purchase follows the Houston, Texas-based company’s Dec. 4 announcement that it will invest some of its surplus cash in the largest cryptocurrency as the adoption of bitcoin treasury for public companies gathers steam.

The company has achieved a bitcoin yield of 127% so far this year, it said in a statement shared with CoinDesk. The yield is the percentage change in the ratio of its bitcoin holdings to its full-diluted shares outstanding over a given period.

Since the investment strategy was announced, the company’s NYSE-traded shares have soared 90%, while bitcoin has added 7%. They closed Friday at $2.28 and were up 2.2% in pre-market trading Tuesday.