最新报道:JPMorgan upgraded Bitcoin miner Marathon Digital Holdings (MARA) to "overweight" from "neutral," citing improved operational efficiency and strong liquidity position, while downgrading peers Iris Energy (IREN) and Riot Platforms (RIOT) to "neutral" due to valuation concerns. The bank noted MARA's recent hashrate growth and cost optimization efforts position it well for potential Bitcoin price appreciation, forecasting BTC could reach $80,000 by end-2025. IREN and RIOT shares fell 3-5% in premarket trading following the ratings change, while MARA gained 7%. Analysts highlighted increasing competition in North American mining sector as firms expand capacity ahead of next year's Bitcoin halving event.