For starters, you are correct. Bitfinex and Tether do share the same CEO - according to a person familiar with the matter.

To those that are in the dark as to what's going on... Tether's coins have become a popular substitute for dollars on cyrptocurrency exchanges worldwide. There are about $2.3 billion of the tokens outstanding as of Tuesday and Tether has to have $2.3 billion backed by the U.S. dollar in case everyone on the Tether market wants to cash out. This is similar to how casinos are required to have cash at hand in case everyone in the casino wins the jackpot... very unlikely, but it can happen.

According to Bloomberg: A document on Tether’s website, compiled by accounting firm Friedman LLP, shows it had $443 million and 1,590 euros ($1,970) in bank accounts as of Sept. 15. Tether tokens were valued at $420 million that day, according to Coinmarketcap.com. Tether hasn’t identified the banks where that money was held, and their names were blacked out in the document.

I hope this clears up any confusion!