Shares of Riot Platforms (NASDAQ: RIOT) jumped on September 24, opening at $17.82 and rising above$19 before 10:00 AM EST. That lifted Riot’s market cap to about $7.04 billion, nudging ahead of MARA’s$6.8 billion valuation to become the second most valued public bitcoin miner. Get these headlines directly to your inbox: subscribe to Blockspace. Riot Platforms produced 484 BTC in July 2025, an 8% increase from June’s 450 BTC, before mining 477 BTC in August, a 2% month-over-month decline, according to th ...