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* Tesla, Intel fall on flagging supply-chain constraints

* Netflix jumps after Ackman builds new stake

* U.S. economy's 2021 growth best since 1984

* Indexes down: Dow 0.42%, S&P 0.82%, Nasdaq 1.43%

NEW YORK, Jan 27 (Reuters) - Wall Street gyrated on Thursday, with a broad rally reversing by mid-afternoon and the S&P 500 flirting with correction confirmation as investors juggled positive economic news with mixed corporate earnings, geopolitical unrest and the prospect of a more hawkish Federal Reserve.

All three major U.S. stock indexes have been whipsawed by uncertainty in recent sessions, marked by wide fluctuations and heightened volatility.

"This is a market that is schizophrenic," said Tim Ghriskey, senior portfolio strategist at Ingalls & Snyder in New York. "There those who believe everything negative has been discounted there are others who believe that the worst is yet to come."

"It’s a period of a lot of uncertainty, it’s been this way all month," Ghriskey added.

The S&P 500 once again threatened to close 10% or more below its all-time high reached on Jan. 3, which would confirm the bellwether index has been in correction since then. It was last 10.1% below that level.

Smallcaps have had a rougher go of it, with the Russell 2000 now more than 20% below its Nov. 8 record high, the level that would confirm the index is in a bear market.

Among a spate of economic data released on Thursday, the Commerce Department's advance take on fourth-quarter GDP shows the U.S. economy in 2021 grew at its fastest pace in nearly four decades.

Markets gyrated wildly following the release on Wednesday of the FOMC statement, which left key interest rates near zero, and Fed Chairman Jerome Powell's subsequent Q&A session during which he appeared to raise the possibility of more rate hikes this year than previously expected, beginning in March.

The fed funds futures market now prices in nearly five rate hikes this year in the wake of Powell's remarks.

Geopolitical tensions continue to simmer, as Russia continues to build up troops along the Ukrainian border and diplomats scramble to avoid conflict in the region.

The Dow Jones Industrial Average fell 143.57 points, or 0.42%, to 34,024.52, the S&P 500 lost 35.65 points, or 0.82%, to 4,314.28 and the Nasdaq Composite dropped 193.59 points, or 1.43%, to 13,348.53.

Fourth-quarter reporting season has hit full stride, with 145 of the companies in the S&P 500 having reported. Of those, 79% have delivered consensus-beating results, according to Refinitiv data.

Analysts now see, on aggregate, year-on-year fourth-quarter earnings growth of 24.2% for the S&P 500, per Refinitiv.

Supply-chain challenges, the engine driving inflation through the recovery from the global health crisis, have been a recurring theme this earnings season.

Intel Corp cited that issue as the reason behind its disappointing first-quarter earnings forecast, which sent its shares tumbling 7.1%.

Intel's dismal outlook weighed on the broader sector, sending the Philadelphia SE semiconductor index down 5.0%.

Shares of Tesla Inc crashed 10.0% after the company warned that supply issues will last throughout 2022. Shares of rivals Lucid Group and Rivian Automotive were both down more than 9%.

Netflix Inc jumped 8.5% following news that billionaire investor William Ackman has amassed a new $1 billion stake in the company.

Apple Inc was modestly lower ahead of its quarterly earnings, expected after the bell.

Chevron Corp, due to report before the bell on Friday, was up 0.7%.

Declining issues outnumbered advancing ones on the NYSE by a 2.60-to-1 ratio; on Nasdaq, a 3.37-to-1 ratio favored decliners.

The S&P 500 posted 17 new 52-week highs and 15 new lows; the Nasdaq Composite recorded 15 new highs and 474 new lows. (Reporting by Stephen Culp in New York Aditional reporting by Bansari Mayur Kamdar and Devik Jain in Bengaluru Editing by Sriraj Kalluvila and Matthew Lewis)