After KOSPI Hit the Sidecar: EWYUSDT Fell 16.42% This Week, With 0 of 31 Weeks Weaker

This week pushed EWYUSDT to the weakest spot in its sample

KOSPI fell 6% intraday and triggered the sidecar mechanism, and the panic did not stay on the Korean index. Binance EWYUSDT, a US equity USDT-margined perpetual, moved from 178.2 USDT to 148.94 USDT this week, a drop of 16.42%. Across a 31-week sample it ranks 31st, with 0 weeks weaker, placing it in the back half of the sample. In the same week KORUUSDT fell 43.6%, SKHYNIXUSDT fell 23.99%, and SAMSUNGUSDT fell 20.71%. For anyone trading Korean equity and Korea ETF contracts, this was not a one-day pullback but a full week of one-way repricing.

Four heavy down days on the daily chart

Here is the EWYUSDT daily series for this week, with 10-12 as the week's start and 10-15 as the data cutoff.

Date	open	close	Change
2026-10-08	184.47 USDT	176.56 USDT	-4.29%
2026-10-09	176.55 USDT	177.49 USDT	0.53%
2026-10-10	177.49 USDT	178.26 USDT	0.43%
2026-10-11	178.26 USDT	178.19 USDT	-0.04%
2026-10-12	178.2 USDT	169.21 USDT	-5.04%
2026-10-13	169.22 USDT	165.54 USDT	-2.17%
2026-10-14	165.55 USDT	155.84 USDT	-5.87%
2026-10-15	155.85 USDT	148.94 USDT	-4.43%

Three days stand out. On 10-12, the first down day of the week, open was 178.2 USDT and close was 169.21 USDT, a drop of 5.04%; the sidecar news landed in this window and price showed no rebound. On 10-14, the largest single-day drop of the week, open was 165.55 USDT and close was 155.84 USDT, down 5.87%, accelerating the earlier drift. On 10-15 it closed at 148.94 USDT, down another 4.43%, meaning the week's final day was still moving lower with no stabilizing close. From 10-08 to 10-11, the largest move was just 0.53% and 10-11 fell only 0.04%, a completely different state from the days after 10-12.

The other three contracts were steeper on the same timeline. KORUUSDT fell 15.01% on 10-12, 17.06% on 10-14, and 14.62% on 10-15. SKHYNIXUSDT fell 9.98% on 10-14, and SAMSUNGUSDT fell 7.39% on 10-14. All four moved in the same direction, just at different magnitudes.

The 30 stronger weeks, up and down

EWYUSDT has a 31-week sample, with 30 weeks stronger than this one; this week ranks 31st, in the back half of the sample. A few original values show how extreme a 16.42% drop is here.

Week start	open	close	Change
2026-03-16	132.25 USDT	127.63 USDT	-3.49%
2026-03-23	127.67 USDT	119.68 USDT	-6.26%
2026-04-06	122.69 USDT	137.83 USDT	12.34%
2026-05-04	161.15 USDT	193.8 USDT	20.26%
2026-06-01	206.49 USDT	176.86 USDT	-14.35%
2026-06-08	176.84 USDT	204.88 USDT	15.86%
2026-07-13	181.54 USDT	162.75 USDT	-10.35%
2026-08-10	166.81 USDT	180.56 USDT	8.24%
2026-10-05	192.01 USDT	178.19 USDT	-7.2%

Among those 30 weeks, the gains were large: 20.26% in the week of 2026-05-04, 15.86% in the week of 2026-06-08, and 12.34% in the week of 2026-04-06. Down weeks existed too, but they fell less than this week: 14.35% in the week of 2026-06-01, 10.35% in the week of 2026-07-13, 7.2% in the week of 2026-10-05, and 6.26% in the week of 2026-03-23. They still count as stronger weeks because their declines were smaller. This week fell 16.42%, ranked 31st, in the back half of the sample, with 0 weeks weaker.

What the trending posts are saying

Trending posts on the Square argue that after KOSPI fell 6% intraday and triggered the sidecar, panic in Korean equities would transmit through ETFs and related single-stock contracts to Binance's Korean equity and Korea ETF contracts (relayed, not the site's view). EWYUSDT and KORUUSDT come up most often, on the reasoning that these two have the most direct exposure to the Korean market, and that a circuit-breaker-style intraday arrangement would show up first in the most liquid contracts. Other posts group SKHYNIXUSDT and SAMSUNGUSDT together, saying the single-day drops in heavyweight names show selling was not confined to the index level.

The direction in those posts matches the daily data: after 10-12 all four contracts weakened together, with EWYUSDT down 16.42% this week, KORUUSDT down 43.6%, SKHYNIXUSDT down 23.99%, and SAMSUNGUSDT down 20.71%. But the causal explanation is a relay, not a confirmed fact; the sidecar mechanism and contract prices are separated by time zones, liquidity, and each contract's own funding structure. Read posts for sentiment and focus, but size positions by your own risk rules.

Three honest points

First, gaps and consecutive down days are different things. EWYUSDT went from 178.2 USDT to 148.94 USDT this week without a meaningful rebound close; 10-13 fell only 2.17%, which looked like a breather, but 10-14 immediately fell 5.87%. A slow intraday drift does not mean selling is over, and judging by a single day's move can be undone by the next candle.

Second, high leverage has no room for error in a week like this. This week fell 16.42%, KORUUSDT fell 43.6%, SKHYNIXUSDT fell 23.99%, and SAMSUNGUSDT fell 20.71%, all far larger than the daily moves. Leverage magnifies the path, not the direction; being right on direction can still get you cleared out in the middle.

Third, funding and the "best week" are conclusions in hindsight. The 30 stronger weeks in the sample were ranked only after this week finished; nobody knew the week of 2026-05-04 would gain 20.26%, and nobody knew this week would fall 16.42%. Treating historical rankings as a forward guide is the same as treating sidecar news as a trading signal.

On fees

Binance's default maker fee is 0.02% and default taker fee is 0.05%. The rebate ratio is 20%, and after the rebate the effective maker fee is 0.016% and the effective taker fee is 0.04%. In a week of consecutive down days with frequent entries and exits, the gap between 0.04% taker and 0.016% maker gets amplified by trade count, so it is worth checking your own fill mix when trading volatile contracts like EWYUSDT.

Source: https://fapi.binance.com/fapi/v1/exchangeInfo

Data as of 2026-10-15; source: Binance official API. Not investment advice.