I don't know whether the amount they paid is correct, but Bitfinex did announce they reached a settlement with the US CFTC. It's top of the Bitfinex announcements page. I quoted the whole announcement below, although I couldn't find an amount paid in it.
Announcements > Bitfinex and CFTC reach settlement
June 02, 2016
Today, the United States Commodity Futures Trading Commission (CFTC) issued an order instituting proceedings against BFXNA Inc. (BFXNA), an entity that conducts business with U.S. customers through the website
www.bitfinex.com. In the order, the CFTC accepted BFXNAs offer of settlement to resolve certain alleged violations of the U.S. Commodity Exchange Act (the Act). A copy of the order is here. In the order and settlement, the CFTC found that BFXNA violated sections 4(a) and 4d(a) of the Act. BFXNA neither admits nor denies the CFTC findings in the order and settlement.
Bitfinex proactively contacted the CFTC in September 2015before the CFTC announced enforcement action involving bitcoin trading platformsto provide information about Bitfinex related to a potential investigation. According to the order, "Bitfinexs cooperation with the Commissions investigation was significant
Bitfinex consistently responded to requests for information fully and quickly, both in writing and via oral presentations."
In response to these constructive discussions with the CFTCs Division of Enforcement, BFXNA has made significant changes to the way in which U.S. customers engage in financed trading on Bitfinex. Bitfinex remains committed to continually improving its customers experience while complying with applicable laws and regulatory requirements.
In closing, we are pleased to announce this settlement with the CFTC. The CFTC has engaged in a productive, open, and timely dialogue with us, and, as a result, we believe we have a better understanding of the regulatory framework governing financed trading on our platform. The Division of Enforcement has demonstrated that, while they will work diligently to enforce existing rules even as they apply them to new markets, they also are sensitive to innovation and development in sectors that the CFTC regulates.
We look forward to providing best-in-class service to U.S. customers. We will continually work to make our customers experience safer and better.
Themerkle confirms the amount of 75k is correct.