(Updated with details on states being allowed to opt out of the Medicaid expansion that Obamacare calls for.)

The U.S. Supreme Court ruled today to uphold the requirement that individuals be insured in President Obama’s healthcare overhaul, but also objected to the expansion of Medicaid under the 2010 law—a mixed ruling that was affecting various health-care-related ETFs differently on a day the broader market fell.

The divided 5-4 High Court ruling, which featured Chief Justice John Roberts breaking with conservative colleagues in writing the majority opinion, deemed the so-called mandate to be the equivalent of a tax. Preserving the mandate means that by 2014, 32 million new individuals will join the pool of customers for drug companies and health care service and equipment providers.

Still, the Wall Street Journal reported that the Court made changes to the Medicaid portion of the law, which could limit the impact all those new patients will have on the bottom lines of health-care-related companies, and might explain why some health care ETFs, such as those focused on biotech, fell more sharply than the broader market.

A total of 19 health-care-related ETF are now listed in U.S., excluding inverse and leveraged funds, according to IndexUniverse’s “Fund Finder.” The broad and popular $4.65 billion Health Care Select Sector SPDR Fund (NYSEArca: XLV) ended about 0.5 percent lower at $37.30 —a bit deeper in the than the broader stock market.

The Dow Jones industrial average retraced most of its early losses to close 24.75 points, or 0.2 percent lower, at 12,602.26. The earlier losses were linked largely to J.P. Morgan Chase’s revelations that trading losses related to the “London Whale” might be as much as $9 billion, or more than four times greater than its initial $2 billion estimate.

Differing Performance

Just over half of XLV is in pharmaceuticals, its biggest subsector allocation. The rest of its top five allocations are: health care equipment at 16 percent, biotechnology at 11 percent, managed health care at 9 percent and health care services at 5 percent.

XLV’s performance was bookended on the one hand by the $1.96 billion iShares Nasdaq Biotechnology Index Fund (NasdaqGM: IBB)—which fell more than 2.6 percent  to $126.55 and, on the other end, by the iShares Dow Jones U.S. Healthcare Providers Index Fund (NYSEArca: IHF)—which closed $1.00 or 1.57 percent higher, at $64.88 a share.

IHF’s relatively strong performance was consistent with a Wall Street Journal report saying stocks of hospital companies were benefiting from the Supreme Court decision. The newspaper also said insurers were hit harder than other areas of the health care industry.

“S&P Capital IQ believes the best-case scenario for the health care industry would be for the Court to rule that the individual mandate is constitutional and that the entire law remains intact,” Jeffrey Loo, an analyst at Standard & Poor's, wrote in a report published earlier this month.

Loo's most-favorable outcome isn’t exactly what transpired, given that the High Court made changes to Medicaid, as the Wall Street Journal reported.

The Supreme Court is allowing individual states to opt out of the expansion of Medicaid that the law calls for, so it’s not yet clear just how different the Patient Protection and Affordable Care Act will look following the highly anticipated Supreme Court decision.

That Medicaid-related wiggle room gives credence to something else Loo warned about in his note: “This ruling would not change the opposition voiced by numerous states and many Republicans.”

Loo also reminded readers that 26 of 50 U.S. states actually filed petitions to block the landmark legislation that was passed by the U.S. Congress in March 2010.

The landmark legislation requires the establishment of marketplaces within each state by 2014 to help currently uninsured Americans obtain health insurance.

Just 14 states have such health care exchanges, which allow customers to compare and shop for health insurance.