U.S. stocks closed slightly lower on Thursday, with the Dow edging into negative territory to extending its losing streak to six sessions as a delay in a closely watched health-care vote raised questions about the Trump administration’s ability to win passage of its ambitious legislative agenda.

Trading was volatile, with major indexes at one point posting solid gains, but then turning lower ahead of the close after House Republican leaders delayed a vote to replace the Affordable Care Act.

Read:Here’s what the health-care vote means for financial markets

The Dow Jones Industrial Average DJIA, -0.87% ended with a loss of 4.72 points at 20,656.58, posting its sixth straight negative session, its longest losing streak since a seven-session run that ended Nov. 4. Despite the recent downtrend, most of the daily decline in the streak were dips of less than 0.1%, as was true for Thursday’s move.

The S&P 500 index SPX, -1.11% fell 2.49 points to end at 2,345.96, a loss of 0.1%. The Nasdaq Composite Index COMP, -1.07% slid 3.95 points to end at 5,817.69, a decline of less than 0.1%.

The day’s trading was driven by the bill’s prospects, but investors care less about the economic impact of the proposal, and more about what it says about President Donald Trump’s ability to enact his economic agenda. The delay in the vote suggests the Republican Party, despite controlling the White House and being the majority party in the House and Senate, could struggle to form a consensus.

“The prospects of the bill are defining everything today, which is creating some concern. The headlines are moving so quickly it’s hard to figure out what’s going on,” said Ian Winer, director of equity sales trading at Wedbush Securities.

“The trading has nothing to do with the health-care aspects of the bill, and everything to do with what it means for tax reform, infrastructure spending, the general ability of these guys to get things done. A lot of the rally has been based on the expectation that these things will get done. If you bring that into question, a lot more risk enters the market,” Winer said.

See also:Infrastructure ETFs stall as Trump plan moves to back burner

Wall Street’s recent weakness has been driven in part by concerns that momentum is slowing for Trump’s economic agenda. On Tuesday, major indexes dropped 1%, breaking a multimonth streak without a decline of that magnitude, in a move that was credited to this political risk. Despite that, U.S. stocks remain solidly higher for the year.

Read:Suddenly, stock-market investors fear Trump will drop the fiscal-policy baton

The day’s losses were broad, with seven of the 11 primary S&P 500 sectors ending lower. Health care XLV, -0.15% was among the biggest losers, down about 0.4%. Among the biggest decliners, Centene Corp. CNC, +1.17% lost 4% while Humana Inc. HUM, +1.29% shed 1.6%.

Deeper losses were offset by a rise in the material sector XLB, -1.72% , which rose 0.45%.

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Read:Dennis Gartman sees at least a 5% drop for stocks—and shades of Watergate

In economic data, first-time jobless claims unexpectedly rose in the latest week, hitting a two-month high.

Stocks to watch:Ford Motor Co. F, -0.68% fell 0.9% after it gave a first-quarter earnings outlook that was below expectations.

Apple Inc. AAPL, -3.17% fell 0.4% after a report that it had acquired Workflow, a popular mobile app for automating tasks, TechCrunch reported Wednesday.

Opinion:Your best defensive bet is…tech stocks?

Five Below Inc. FIVE, +1.87% surged 11% after the retailer reported forecast-beating earnings and said it would open 100 new stores in 2017.

Elliot Management Corp. has surfaced as a key player in a $24 billion standoff between Akzo Nobel NV DE:AKZO and PPG Industries Inc. PPG, -2.69% . Elliot on Wednesday threatened to use corporate rules to call a special shareholders meeting try to try to force Akzo to at least talk with PPG. Shares of PPG rose 0.4%.

Other markets: Asian stocks ADOW, +0.33% had a largely quiet session, while European stocks SXXP, -0.66% hovered near their lows of the week, with investors reluctant to make big moves ahead of the U.S. health care vote.