VeriFoneVeriFone, the big payments company that has more than half of the U.S. market for credit-card terminals, just ousted its CEO, Doug Bergeron.VeriFone's stock rose 6 percent today, following Bergeron's departure.There's a host of possible reasons—disappointing results, ongoing shareholder lawsuits, and an admission of illegal business dealings with customers in Iran.Now Square has been valued at $3.25 billion, and VeriFone is worth less than two-thirds of that.VeriFone attempted to take on Square's smartphone-attached credit-card reader with a knockoff product called Sail. It cancelled Sail late last year, with Bergeron declaring the mobile-payments business "unprofitable."From: Doug Bergeron. Subject: To All of YouDear friends,I write to you today with thoughts that are full of emotion and filled with love for you and our company.Late last week, the VeriFone board met, and together with my agreement decided that the time is right for new leadership of the Company. We have had our victories together as well as our stumbles. Recently, we disappointed our investors with some terrible results that I have largely blamed on our own issues. This was my responsibility and I accept the consequences.I have been your CEO for almost 12 years and I have enjoyed every single day here. In 2001, we purchased the company from Hewlett Packard for $50 million dollars (which we mostly had to borrow) and today VeriFone's enterprise value is about $3 billion dollars. We had 800 employees and under $300 million in revenue in the first year. Today, our revenues are six times larger and we employ almost 5, 000 people around the world. I am so very proud of this achievement. It was one of the most remarkable turnaround investments in a generation.I actually do not recall much about life before VeriFone. I was CEO of VeriFone before I met my wife, and we now have 3 children together who have only known their father in this role. Those of you who know me best know that there is very little daylight between my personal identity and my role here. I will have to rediscover myself over the coming weeks and months, and I hope to discover some long lost talents.I tried my best, always, to be an honorable leader and to make you proud of me and proud to work here. I know we created a special culture of entrepreneurship, risk taking, high expectations, and fun.You will have an opportunity in the days ahead to be part of a new and rejuvenated company. We have many strong leaders who I'm sure will be asked to do even more. This is a great opportunity for all of you. The culture that we have created together is alive and well, and it will carry this company through this transition.