The CEO of a $3 billion startup that recently raised $280 million is suddenly stepping down

Docusign CEO Keith Krach has told the company in an internal memo that he'll be stepping down, Recode reported on Friday.

Krach didn't explain the reason for his resignation, but said he'll stay CEO until the company finds his successor. He also said he'll remain the company's chairman for at least another 3 years.

"Let me start by saying, we are at the beginning of this journey, not the end," Krach wrote in the company-wide letter.

Krach's departure comes as a bit of a surprise, especially considering Docusign just raised $280 million at a $3 billion valuation in May. Whatever the reason is, it doesn't send a positive signal when the CEO suddenly steps down.

Docusign is a company that provides e-signature technology, allowing people to sign documents over the web. It's raised over $500 million so far from investors like Google, SAP, and Salesforce.

Krach, 57, is a serial entrepreneur with a proven track record of growing companies. His last company, Ariba, was sold to SAP for $4.3 billion, and since joining Docusign in 2012, he grew the company's userbase to well over 50 million unique users across 188 countries.