The US GP has been listed as provisional on the latest version of the 2016 F1 calendar, which was published today after a meeting of the World Motor Sport Council in Paris.
Although the Austin race still has its previously announce date, the FIA says that it is “subject to agreement with the promoter and the ASN.”
As previously reported the race has lost some 20% of its subsidy from the Texas Major Events Trust Fund, with a reduction from $25m to $19.5m for this year, and COTA boss Bobby Epstein has made it clear that the race could be under threat.
The only change from the previously published version of the schedule is that Mexico has moved forward by a week from November 7 to October 30, which means it is again a back-to-back with Austin. Bernie Ecclestone had originally twinned the race with Brazil.
2016 F1 World Championship
20 March Melbourne Australia
3 April Bahrain Bahrain
17 April Shanghai China
1 May Sochi Russia
15 May Barcelona Spain
29 May Monte Carlo Monaco
12 June Montreal Canada
19 June Baku Azerbaijan*
3 July Spielberg Austria
10 July Silverstone United Kingdom
24 July Budapest Hungary
31 July Hockenheim Germany
28 August Spa-Francorchamps Belgium
4 September Monza Italy
18 September Singapore Singapore
2 October Sepang Malaysia
9 October Suzuka Japan
23 October Austin USA**
30 October Mexico City Mexico
13 November Sao Paolo Brazil
27 November Abu Dhabi United Arab Emirates
*race start to be scheduled to avoid conflict with the conclusion of the 24 Hours of Le Mans
**subject to agreement with the promoter and the ASN
Adam Cooper's F1 Blog 
With 21 races on the schedule it’s obvious Bernie can play hardball with COTA and drop Austin if they don’t pay the contracted fees. Hence the asterisk on their date.