August 20 market wrap: Dow slides as VIX jumps
U.S. indexes fell 0.72%–1.32% on August 20 as the VIX rose to 16.01 and the 10-year yield reached 4.69%. MRVL gained 5.79%, while RKLB lost 3.81%.
YieldCove Desk
2 min read
S&P 500
7,641.16
−0.87%
Nasdaq-100
29,213.16
−0.72%
Dow
52,759
−1.32%
Cboe VIX
16.01
+7.52%
Stocks retreat as the Dow lags
U.S. stocks finished Thursday, August 20, 2026 lower across the three headline benchmarks. The S&P 500 closed at 7,641.16, down 66.82 points, or 0.87%. The Nasdaq-100 lost 212.84 points, or 0.72%, to 29,213.16, while the Dow Jones Industrial Average fell 704 points, or 1.32%, to 52,759. The Dow’s larger percentage decline made the session broader than a technology-only pullback.
| Market | Close | Daily move |
|---|---|---|
| S&P 500 | 7,641.16 | −0.87% |
| Nasdaq-100 | 29,213.16 | −0.72% |
| Dow Jones Industrial Average | 52,759 | −1.32% |
| Cboe VIX | 16.01 | +7.52% |
Volatility rises as the 10-year yield adds four basis points
The Cboe VIX closed at 16.01, up 1.12 points, or 7.52%, from 14.89 on August 19. The U.S. Treasury’s daily par-yield curve placed the 2-year yield at 4.19%, unchanged from the prior market day, and the 10-year yield at 4.69%, up four basis points from 4.65%. Higher long-term yields and a higher volatility index accompanied the equity decline, but a single session does not establish a lasting regime.
Wheel lens
A VIX close of 16.01 summarizes expected S&P 500 volatility over roughly 30 days. It is not an executable option quote for MRVL or RKLB. A contract-level review still requires the exact expiry and strike, bid and ask, open interest, event calendar, full collateral or share obligation, and assignment tolerance.
Marvell rallies while Rocket Lab retreats
Within YieldCove’s current watchlist, Marvell Technology (MRVL) closed at $251.01, up $13.74, or 5.79%, from $237.27. Rocket Lab (RKLB) finished at $72.95, down $2.89, or 3.81%, from $75.84. Cboe’s delayed closing records and Nasdaq’s stock screener matched on both closing prices and dollar moves. Those sources establish the moves; closing records alone do not prove a company-specific cause.
| Ticker | Close | Daily move |
|---|---|---|
| MRVL | $251.01 | +$13.74 / +5.79% |
| RKLB | $72.95 | −$2.89 / −3.81% |
Moves of roughly 4%–6% can change option moneyness faster than the broad indexes imply. A rising underlying can move a covered-call strike closer to the stock price, while a falling underlying can reduce the cushion on a cash-secured put. Neither move identifies an attractive new contract by itself: the next session’s bid-ask spread, implied volatility, skew and event risk still matter.
For readers monitoring assignment risk, each dated close is a reference point rather than an order instruction. Option premiums are quoted per share, one standard contract normally represents 100 shares, and the full cash or delivery obligation should be considered before interpreting the percentage move. Rebuilding the exact contract quote after the market reopens may materially change the picture.
What the close establishes
The broad index decline, higher VIX, higher 10-year Treasury yield, MRVL gain and RKLB decline are verified August 20 closing facts. They do not identify a favourable strike, premium or trade. This market wrap is educational information only, not personalized financial advice or an order instruction.
Sources
- [1]S&P 500 delayed closing quote — August 20, 2026 — Cboe Global Markets · Accessed 2026-08-20 · Tier 1
- [2]Nasdaq-100 delayed closing quote — August 20, 2026 — Cboe Global Markets · Accessed 2026-08-20 · Tier 1
- [3]Dow Jones delayed closing quote (DJX) — August 20, 2026 — Cboe Global Markets · Accessed 2026-08-20 · Tier 1
- [4]Cboe VIX delayed closing quote — August 20, 2026 — Cboe Global Markets · Accessed 2026-08-20 · Tier 1
- [5]Daily Treasury par yield curve rates — 2026 — U.S. Department of the Treasury · Accessed 2026-08-20 · Tier 1
- [6]Marvell Technology delayed closing quote — August 20, 2026 — Cboe Global Markets · Accessed 2026-08-20 · Tier 1
- [7]Rocket Lab delayed closing quote — August 20, 2026 — Cboe Global Markets · Accessed 2026-08-20 · Tier 1
- [8]Official U.S. stock screener closing data — August 20, 2026 — Nasdaq · Accessed 2026-08-20 · Tier 1
This content is for informational and educational purposes only and is not financial advice. Options involve risk and are not suitable for every investor. Do your own research before trading.
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