Mark Cuban Spends 'Most' of His Time Using This Decades-Old Communication Method. Here's Why He Prefers It. Here's how the tech billionaire gets his inbox from 1,000 emails to 20 in one day (with barely any AI).

Despite all the advancements in technology, billionaire investor Mark Cuban, 66, spends most of his day reading and responding to emails.

In a Wednesday interview with Business Insider, Cuban said that he receives "700 to 1,000 emails" a day through his Gmail account, and he uses three phones, two Android and one iPhone, "to manage everything."

Related: Mark Cuban Says 60 Is the New 40. He Follows 3 Habits to Stay Youthful.

"I spend most of my day trying to get my unreads under 20," Cuban told BI.

He praised email for being "asynchronous," meaning that he can respond at any time from wherever he is in the world, and ubiquitous because "everyone" has an email address. Responding to a message is also "fast," especially with Google's auto-reply suggestions, Cuban said.

Cuban says he keeps his inbox organized with folders and has "never" considered hiring someone to help manage his emails. He is only away from his inbox for a full day or longer for "extraordinary situations, like a special event for a family member," he told BI.

Cuban says he uses his unread emails as reminders of what he needs to get done that day. He only uses AI to write the autoreply messages, preferring instead to personalize longer emails and noted that he would rather process emails than sit through "long, boring meetings," or send a Slack message or text because he can quickly search through emails years later.

"I have emails going back to the 90s," Cuban told BI.

^{Mark Cuban. Photo by Julia Beverly/WireImage}

Still, using Gmail could pose a cybersecurity risk. Cuban's Google account was hacked in June 2024 after he received a call from a fake Google employee. The bad actor said that Cuban's Gmail had an intruder and faked Google's recovery methods to receive the credentials for the account. The hacker got access to Cuban's email and locked him out.

The hacking hasn't stopped Cuban's love of email, however.

Cuban rose to fame as an investor on ABC's "Shark Tank" for the last 15 seasons, appearing in his final episode in May. He told CNBC that same month that he invested about $33 million in businesses during his time on the show and received $35 million in cash returns. He holds equity in those businesses that are now worth at least $250 million, he disclosed.

Related: Mark Cuban Compares AI Taking Jobs to When There Were 'Millions of Secretaries'

Cuban's first BIZ Experiencesial venture was MicroSolutions, a software reseller that sold PCs, software, and training to businesses. He grew the company to nearly $36 million in annual sales and 80 employees before selling it to CompuServe, a subsidiary of H&R Block, for $6 million in 1990.

Cuban then founded AudioNet, the first video streaming company in the world. The startup, which became Broadcast.com, was sold to Yahoo for $5.7 billion in 1999, making Cuban a billionaire.

In 2022, Cuban co-founded Cost Plus Drug Company, an online discount pharmacy that delivers more than 2,300 prescription medications.

Cuban is now worth $8.6 billion, according to the Bloomberg Billionaires Index.

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