In an age when most bankers use keyboards to communicate with each other, a small group of the Wall Street elite refuses to say anything substantive in an email, text or chat, and some will not communicate digitally at all.

This group, which includes top bankers like JPMorgan Chase & Co Chief Executive Officer Jamie Dimon and powerful investors like Carl Icahn and Berkshire Hathaway Inc’s Warren Buffett, were eschewing electronic communications long before the probe of U.S. presidential candidate Hillary Clinton’s emails and the recent hacks of her campaign manager’s account made headlines.

Some on Wall Street are nostalgic for a time when in-person conversations or phone calls were the norm, but others believe the words they type and send can come back to haunt them. Prosecutors have built insider trading, mortgage fraud and rate-rigging cases on embarrassing emails over the past several years, and they are often the most memorable part.

Recent email woes among Washington power players have provided yet another reason for bankers to try to protect private correspondence from prying eyes.

Dimon uses email but is known to keep his replies short and factual, favoring “yes,” “no” and “thank you.”

That behavior was evident in company emails released by a U.S. Senate committee investigating JPMorgan’s $6.2 billion “London Whale” derivatives trading loss. In one message, Dimon replied with a simple “I approve,” showing some responsibility but giving no sense of how deeply he was involved with the decision to change risk tolerances at the bank.

After hearing a passing reference to regrettable emails during an interview at a conference two years ago, Dimon volunteered: “Don’t send emails after you’ve had a drink.”

A JPMorgan spokesman would not comment further.

Other top investors like Icahn and Buffett rely on their assistants to send and receive messages. Buffett’s assistant, Debbie Bosanek, prints out emails for the billionaire investor.

Although the investors are averse to two-way digital correspondence, both blast out carefully curated messages on their Twitter accounts, with Icahn attracting 304,000 followers and Buffet, 1.2 million.

Icahn has often used the tool to promote investments or political views, while Buffett has been relatively mum, tweeting just nine times.

Ariel Investments chief John W. Rogers also shuns email, which he has described to associates as a “distraction.” His staff filters important messages, prints them out and puts them on his chair for review, according to spokeswoman Merrillyn Kosier. He prefers to speak with employees in person or over the phone.

“I do think there is certain cautiousness today around email,” said Virginia Healy-Tangney, a senior lecturer at the MIT Sloan School of Management who focuses on managerial communication. “Since the financial crisis, executives really have to be prepared for anything they say to potentially end up on the front page of the New York Times.” (Reporting by Olivia Oran in New York; Additional reporting by David Henry, Lawrence Delevingne and Jennifer Ablan in New York.)