The pace of enrollment slowed somewhat in January compared December, but more than a million new people signed up.
Federal health officials also touted the fact that 27 percent of them were between the ages of 18 and 34, a demographic coveted by insurance companies.
Marks says young folks signing up will help keep premiums down in the future, but only if they're healthy.
“We often talk about young people as a proxy for healthy people because, on average, young people are healthier than older people but what we really ought to be looking for are healthy people.”
As of now, about 200,000 Texans have signed up for the plans at HealthCare.gov.
That's fewer than in Florida, although Texas has a higher proportion of uninsured residents.
Marks says that's a little disappointing, because at least two million uninsured Texans could be eligible for the plans.
There's also a lot the report doesn't say.
It doesn't reveal how many of the people purchasing new coverage were actually uninsured before.
Some of them may be switching plans to get a government subsidy or better plan features.
There's also no information on race or ethnicity.
“And in state that has a large and growing Hispanic population, where there have been concerns about how we reach out to the Hispanic population, it would be very interesting and helpful to know which groups of people have been able to sign up and which ones are not.”
The deadline for signing up is March 1.
After that, enrollment is closed for 2014 and some uninsured people will face a small tax penalty.