Bitcoin (BTC) mining profitability fell 7.4% in March, investment bank Jefferies said in a research report Friday.

The drop was due to a 11.2% decline in the average bitcoin price and a 9.1% drop in transaction fees, the report said.

U.S.-listed miners mined 3,534 bitcoin in March versus 3,002 in February, Jefferies said, and these companies accounted for 24.8% of the total network last month, compared to 23.6% the month previous.

MARA Holdings (MARA) produced the most bitcoin in March, with 829 tokens, the report said, followed by CleanSpark (CLSK) with 706 BTC.

MARA also had the largest installed hashrate, at 54.3 exahashes per second, with CleanSpark the second-largest at 42.4 EH/s, the report added.

Looking at April, Jefferies noted bitcoin is broadly unchanged while the S&P 500 stock index is down 6%. U.S. dollar weakness may be responsible for some of that outperformance, said the bank.