The mood was largely cautious amid concerns about growth and rising inflation. Investors also looked ahead to the Fed minutes, due later in the day.
The benchmark SMI, which climbed to 11,192.68 earlier in the session, dropped to a low of 11,130.44 before finally settling at 11,128.19 with a marginal loss of 2.25 points.
Credit Suisse fell more than 4%. Logitech drifted down 2.4%, while ABB, Partners Group, Swiss Re, Holcim, Sika, Geberit, UBS Group and Zurich Insurance Group lost 1 to 1.7%.
Nestle climbed nearly 1.5%. Lonza Group, Roche Holding and Novartis posted modest gains.
Swiss Life Holding gained about 0.3%. The insurer reported higher half-year net profit and confirmed FY24 targets.
In the Mid Price Index, AMS ended more than 6% down. Zur Rose declined 5.72% and Julius Baer ended 4.1% down.
Adecco, Schindler Ps, Temenos Group, George Fischer, Schindler Holding and VAT Group lost 2.5 to 3.1%.
Tecan Group rallied 8.28%. Bachem Holding surged 1.3% and Lindt & Spruengli gained nearly 1%. SIG Combibloc ended 0.73% up.