But in recent days the plan's flaws have been exposed, from its nearly nonfunctional website to the sticker shock of higher insurance premiums and dropped coverage for those with pre-existing plans.
(Read more: White House knew millions couldn't keep health plans)
Health-care stocks have gained 32 percent this year, but that surge could be at stake if deeper changes are needed or the program collapses.
"The natural market reaction certainly should be to avoid those health-care stocks that would benefit with a smooth transition to Obamacare," said Art Hogan, managing director at Lazard Capital Markets in New York. "It's hard to tell how long it would take to right the ship, but it could be a bumpy road."
(Read more: 8 must-know Obamacare facts)
Hogan said service-oriented stocks such as hospitals would take the first hit.
Initial market reaction was muted.
The SPDR Health Care Select Sector exchange-traded fund gained about 0.4 percent in morning action and was in fact the third-best performer of an otherwise uneventful session.