Insight Guru Inc.
08/19/2026 | Press release | Distributed by Public on 08/18/2026 23:07
S&P 500 Movers | Winners: SNDK, COHR, FIX | Losers: CVNA, CHTR, STZ
A day of modest index declines hid significant moves in individual stocks, raising questions about momentum.
The S&P 500 returned -0.5% on a day of broad but shallow declines. Yet the session's extremes were anything but modest, with the day's top performer, SanDisk (SNDK), returning +8.9% while the weakest name, Carvana (CVNA), returned -7.3%.
This contrast raises a critical question for any investor scanning the tape: are these sharp, single-day moves isolated noise, or do they reflect a deeper trend? The day's biggest winners and losers are below.
Monday's S&P 500 Winners
The 10 stocks with the highest returns on the last trading day:
| # | Ticker | Company Name |
1-D Returns |
YTD Returns |
|---|---|---|---|---|
| 1 | SNDK | SanDisk | 8.9% | 652.7% |
| 2 | COHR | Coherent | 7.8% | 90.3% |
| 3 | FIX | Comfort Systems USA | 6.0% | 101.9% |
| 4 | TER | Teradyne | 5.8% | 129.1% |
| 5 | AMAT | Applied Materials | 5.5% | 108.8% |
| 6 | MRVL | Marvell Technology | 5.5% | 176.2% |
| 7 | WDC | Western Digital | 5.3% | 211.4% |
| 8 | PWR | Quanta Services | 5.3% | 71.2% |
| 9 | LITE | Lumentum | 4.6% | 162.9% |
| 10 | GLW | Corning | 4.3% | 98.5% |
Monday's S&P 500 Losers
And the 10 stocks with the lowest returns:
| # | Ticker | Company Name |
1-D Returns |
YTD Returns |
|---|---|---|---|---|
| 1 | CVNA | Carvana | -7.3% | -17.0% |
| 2 | CHTR | Charter Communications | -6.6% | -31.0% |
| 3 | STZ | Constellation Brands | -6.2% | -3.4% |
| 4 | ALGN | Align Technology | -5.6% | 9.6% |
| 5 | TTD | Trade Desk | -5.2% | -64.7% |
| 6 | TAP | Molson Coors Beverage | -4.7% | -10.8% |
| 7 | LHX | L3Harris Technologies | -4.6% | -4.5% |
| 8 | KKR | KKR | -4.5% | -14.1% |
| 9 | CNC | Centene | -4.5% | 56.5% |
| 10 | APO | Apollo Global Management | -4.4% | -6.3% |
Is today's strength just a one-day story?
For several names, the answer is no. SanDisk (SNDK) appears on both the one-day and one-month winners lists, and its one-month return is +31.9%. The company's revenue also grew 175.3% over the last twelve months. Teradyne (TER) shows a similar persistence with a one-month return of +37.5%.
This pattern also holds for weakness. Trade Desk (TTD) appears on both the one-day and one-month losers lists, with a one-month return of -27.9%. Some of today's most significant moves are clearly extensions of trends that have been building for weeks.
Movers Over The Last Week
Widening the window to five trading days, these are the strongest and weakest S&P 500 names:
| # | Ticker | Company Name |
1-W Returns |
YTD Returns |
|---|---|---|---|---|
| 1 | SNDK | SanDisk | 44.3% | 652.7% |
| 2 | STX | Seagate Technology | 24.2% | 262.1% |
| 3 | WDC | Western Digital | 22.3% | 211.4% |
| 4 | SMCI | Super Micro Computer | 21.7% | 30.8% |
| 5 | TER | Teradyne | 21.4% | 129.1% |
| 6 | LITE | Lumentum | 19.1% | 162.9% |
| 7 | MU | Micron Technology | 17.5% | 254.7% |
| 8 | CIEN | Ciena | 14.8% | 90.4% |
| 9 | FIX | Comfort Systems USA | 12.4% | 101.9% |
| 10 | MRVL | Marvell Technology | 12.4% | 176.2% |
| # | Ticker | Company Name |
1-W Returns |
YTD Returns |
|---|---|---|---|---|
| 1 | TPR | Tapestry | -21.7% | 1.5% |
| 2 | ULTA | Ulta Beauty | -10.1% | -18.5% |
| 3 | MOS | Mosaic | -9.5% | -10.2% |
| 4 | LULU | Lululemon Athletica | -9.4% | -44.3% |
| 5 | FSLR | First Solar | -9.0% | -16.6% |
| 6 | IDXX | IDEXX Laboratories | -8.3% | -19.3% |
| 7 | APP | AppLovin | -8.0% | -53.7% |
| 8 | CSCO | Cisco Systems | -7.9% | 48.7% |
| 9 | ROST | Ross Stores | -7.7% | 31.1% |
| 10 | DECK | Deckers Outdoor | -7.5% | -13.1% |
Movers Over The Last Month
And over the last 21 trading days:
| # | Ticker | Company Name |
1-M Returns |
YTD Returns |
|---|---|---|---|---|
| 1 | SMCI | Super Micro Computer | 58.3% | 30.8% |
| 2 | ZBRA | Zebra Technologies | 38.8% | 52.9% |
| 3 | TER | Teradyne | 37.5% | 129.1% |
| 4 | NEM | Newmont | 34.1% | 21.0% |
| 5 | LDOS | Leidos | 33.6% | -20.7% |
| 6 | LITE | Lumentum | 32.2% | 162.9% |
| 7 | WDAY | Workday | 32.0% | -11.0% |
| 8 | SNDK | SanDisk | 31.9% | 652.7% |
| 9 | PLTR | Palantir Technologies | 30.3% | -2.9% |
| 10 | IT | Gartner | 27.8% | -29.0% |
| # | Ticker | Company Name |
1-M Returns |
YTD Returns |
|---|---|---|---|---|
| 1 | CHRW | C.H. Robinson Worldwide | -30.6% | -9.3% |
| 2 | TTD | Trade Desk | -27.9% | -64.7% |
| 3 | APP | AppLovin | -26.5% | -53.7% |
| 4 | DVA | DaVita | -25.4% | 55.5% |
| 5 | HONA | Honeywell Aerospace | -23.7% | n/a |
| 6 | LII | Lennox International | -23.5% | -13.8% |
| 7 | ROL | Rollins | -19.8% | -39.3% |
| 8 | DECK | Deckers Outdoor | -15.4% | -13.1% |
| 9 | FICO | Fair Isaac | -15.3% | -37.0% |
| 10 | PODD | Insulet | -14.8% | -50.9% |
A big move is a starting point, not a conclusion.
The tables of winners and losers shown earlier are best used as a map of market attention. A stock's appearance on these lists is information about heightened activity and risk, never an instruction to buy or sell. The disciplined follow-up is always to look past the ticker and into the business itself.
A daily movers list simply flags names for potential homework. It identifies where the action is, but the real work of understanding the value and prospects of a company begins after the market closes.
Either side of these lists can be a lead worth following, with the same follow-up question: does the business back the move? For the winners, our Guidance Momentum screen tracks which companies raised their own forward numbers. For the losers, our Buy the Dip screen flags which marked-down names still have the fundamentals to recover.
The Tape Rewards Attention. It Punishes Reaction
Big daily moves pull hard at both greed and fear, and acting on either, day after day, is how most portfolios end up trailing the index they were trying to beat.
The Trefis High Quality (HQ) Portfolio is built for the opposite reflex: about 30 quality businesses screened for the fundamentals that survive volatile stretches, held with rules instead of reactions. It has a track record of outpacing a benchmark that combines the three major indices - the S&P 500, S&P Mid-cap, and Russell 2000. Read the movers daily; trade them rarely.
Insight Guru Inc. published this content on August 19, 2026, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on August 19, 2026 at 05:08 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]