2016: Equal Employment Opportunity Commission (EEOC) released final regulations under Title I of the ADA and Title II of GINA regarding wellness programs.
Regulations apply to any participation-based and/or outcomes-based programs that include disability-related inquires and/or medical examinations (no medical exam or disability inquiry, no problem)
ADA and GINA regulations limit the maximum reward or penalty for employee or spouse participation to 30% of the total cost of self-only coverage
30% limit includes financial rewards and in-kind incentives, and there is no “de minimis” rule for cast or non-cash incentives
2017: AARP sued EEOC, arguing the 30% limit could be a significant cost to employees and the 30% of the total cost of coverage penalty or incentive makes the program involuntary
Court asked EEOC to justify the 30% limit, but the 30% limit was deemed “arbitrary and capricious.”
2018: Court indicated the 30% limit portion of EEOC regulations shall be vacated as of 1/1/2019.
It’s up to the EEOC to issue new guidance or do nothing by 1/1/2019.
These regulations only apply to wellness programs requiring the completion of a medical exam and/or responding to disability-related health inquiries.
What could happen? We present speculation from various sources.
Employers could eliminate incentives for health screenings while waiting for new guidance.
Without ADA incentive limit rules, employers may feel free to raise participatory wellness program incentives to 100% of the employee’s premium cost. 
Outcomes-based programs are just about done, as they typically require four-figure penalties or incentives to drive participation. This assumes the EEOC will lower its incentive/penalty percentage with new or clarified rules. 
If the old rules are vacated by 1/19, employers trying to figure out how to create a voluntary wellness program are flying blind. 
 Jim Pshock, "Recap from the January 30th Webinar," Bravo, 2 February 2018, https://www.bravowell.com/2018/02/02/recap-january-30th-webinar
 Barbara Zabawa, "Wellness Incentives are Not Dead Yet: Potential Outcomes from the AARP v. EEOC Order," Shortlister, 11 January 2018, https://blog.myshortlister.com/2018/01/11/wellness-incentives-are-not-dead-yet
 Al Lewis, "AARP v. EEOC: On the Contrary, it is Almost Time to Panic," Shortlister, 1 February 2018, https://blog.myshortlister.com/2018/02/01/aarp-vs-eeoc-on-the-contrary-it-is-almost-time-to-panic
 Andie Burjek, "How Employers Can Shift their Wellness Program Plan Design Under Changing Regulations," Workforce, 31 January 2018, http://www.workforce.com/2018/01/31/employers-can-shift-wellness-program-plan-design-changing-regulations/