* Bearish comments by DoubleLine's Gundlach weigh on indexes
* UnitedHealth shares hit by ruling against Affordable Care Act
* Amazon, retailers drop on Britain's ASOS profit warning
* Goldman hits two-year low on Malaysia charges in 1MDB probe
* Indexes down: Dow 2.11 pct, S&P 500 2.08 pct, Nasdaq 2.27 pct (Updates to market close)
By April Joyner
NEW YORK, Dec 17 (Reuters) - Wall Street's major indexes all slid more than 2 percent on Monday, with the benchmark S&P 500 closing at its lowest level in 14 months, on concerns of slowing economic growth ahead of a highly-anticipated decision from the Federal Reserve this week on the course of interest-rate hikes.
The S&P 500 hit its lowest level since October 2017 to breach lows reached during its sell-off in February. The small-cap Russell 2000 index confirmed a bear market, having fallen more than 20 percent from its Aug. 31 closing high.
A profit warning from British retailer ASOS raised concerns about weakening consumer strength, despite robust U.S. retail sales data on Friday. The National Association of Home Builders Housing Market Index indicated homebuilder sentiment had fallen to a three-and-a-half-year low.
The S&P 500 briefly erased its losses in late morning trade, but the index resumed its steep decline after Jeffrey Gundlach, chief executive of DoubleLine Capital, said that U.S. stocks were in a bear market.
Concerns about flagging consumer sentiment pushed down S&P 500 consumer discretionary stocks, which tumbled 2.8 percent. Shares of Amazon.com Inc dropped 4.5 percent, creating the biggest drag on the S&P 500 and the Nasdaq. Retail stocks declined overall, with the S&P 500 Retailing Index falling 3.4 percent.
Investors said market skittishness was likely to persist heading into the Federal Open Market Committee meeting on Tuesday and Wednesday.
An indication that the Fed would slow its pace of interest-rate hikes could calm markets, but the central bank's intentions remain unclear, said Ryan Detrick, senior market strategist at LPL Financial in Charlotte, North Carolina.
"We're all holding our breath for the Fed," Detrick said. "If the Fed takes its foot off the pedal for the first half of next year, that would get rid of one uncertainty."
The Dow Jones Industrial Average fell 507.53 points, or 2.11 percent, to 23,592.98, the S&P 500 lost 54.01 points, or 2.08 percent, to 2,545.94 and the Nasdaq Composite dropped 156.93 points, or 2.27 percent, to 6,753.73.
The Cboe Volatility Index, the most widely followed gauge of expected near-term gyrations for the S&P 500, finished up 2.89 points at 24.52, its highest close in seven weeks.
Shares of insurer UnitedHealth Group Inc fell 2.6 percent after a federal judge late on Friday ruled that the Affordable Care Act, commonly known as Obamacare, was unconstitutional. UnitedHealth was the biggest drag on the Dow.
Johnson & Johnson shares fell for a second consecutive session following a Reuters report that the company knew for decades that its baby powder contained asbestos. J&J shares ended 2.9 percent lower.
Shares of Goldman Sachs Group Inc dropped 2.8 percent to a two-year low after Malaysia filed criminal charges against the bank in connection with an investigation into suspected corruption and money laundering involving the sovereign wealth fund 1MDB. The stock has the biggest year-to-date percentage decline among Dow components.
Twitter Inc shares slid 6.8 percent after the social media company warned of suspicious traffic from China and Saudi Arabia and disclosed an issue that could have revealed the country code of its users' phone numbers.
Declining issues outnumbered advancers on the NYSE by a 5.55-to-1 ratio; on Nasdaq, a 4.31-to-1 ratio favored decliners.
The S&P 500 posted one new 52-week high and 116 new lows; the Nasdaq Composite recorded 10 new highs and 556 new lows.
Volume on U.S. exchanges was 9.44 billion shares, compared to the 8.01 billion average over the last 20 trading days. (Reporting by April Joyner; additional reporting by Saqib Iqbal Ahmed in New York and Amy Caren Daniel in Bengaluru; Editing by Bill Berkrot)