What is an 834?


The magic number of Obamacare, “834” is what insurers call electronic data files sent from the federal health insurance website to insurance companies.


834 EDI transmissions are sent to insurers every day around 6:00 PM, and their contents are essential to successful enrollment. They contain information on insurance applicants including their policy number, name, contact information and the kind of health plan they chose.


An 834 might look a bit like this:


The file is a reporting tool visible only to those with access to the federal data hub’s back-end and the insurer’s computer system. Consumers don’t see the 834, but it should include the information they input when filling out an application and selecting a health plan.


An 834 is a technical form, intended for computers to read, letting the insurance company’s system know who’s applying and what products they want. It was also a major problem in HealthCare.gov’s opening months.


In the early days of the marketplace, 834s were subject to the glitches the website experienced. Insurers indicated that the files were being received with incorrect information, which made it among the top concerns from October to December 2013.


If an 834 EDI transmission came in wrong, it could unintentionally:

  • Enroll you in the wrong health plan
  • Exclude family members from your policy
  • Prevent identity verification


What Data Does an 834 Contain?

834s hold enrollment information that you provide when you apply for insurance online through HealthCare.gov. This data includes:

  • Social Security Numbers
  • Dependent children and spouse information
  • The plan you chose


How 834 Transmissions Work


Prior to the health insurance exchanges, 834 transmissions had already been used for several decades so that employers could tell their insurers which employees were using group health benefits.


Using this model, the federal agencies running the Obamacare website would operate like the rest of the industry. The Centers for Medicare and Medicaid Services transmits data the same way as everyone else, which makes sense.


CMS created a 40-page manual on how to use the 834 system, and where the files end up.


The manual contains this diagram to show federal workers how it works. The section labeled “EFT” shows where the files turn up, standing for Electronic File Transmission.




This document tells the reader that the 834 transmission is the only form in the vastness of the federal website’s back-end that tells insurers who has enrolled in one of their plans.


This file is needed to create membership identification cards, so that customers can use their insurance card and the insurer can pay claims.