U.S. stock benchmarks finished the session slightly higher on Wednesday, with the slight gains enough to notch a fresh all-time high for the S&P 500 index. Gains for the broad-market benchmark were driven by a surge in the energy sector, up 3%, and financials, 1.1% higher, to help the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.72% eke out a 0.2% gain to reach 3,669, despite over 1% declines in materials and real estate. The Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA -0.57% finished 0.2% higher, as an 8.5% decline in Salesforce.com /zigman2/quotes/200515854/composite CRM -1.14% , after its announced $27.7 billion buy of Slack Technologies /zigman2/quotes/212180539/composite WORK -0.29% was officially announced late Tuesday, was offset by gains in Boeing Co. /zigman2/quotes/208579720/composite BA -2.66% , Goldman Sachs /zigman2/quotes/209237603/composite GS -2.23% , Walt Disney Co. /zigman2/quotes/203410047/composite DIS -1.15% , Chevron Corp. /zigman2/quotes/205871374/composite CVX -3.56% , American Express Co. /zigman2/quotes/203805826/composite AXP -1.32% and Walgreens Boots Alliance Inc. /zigman2/quotes/203410933/composite WBA -0.81% . The Nasdaq Composite, however, finished less than 0.1% lower at 12,349. Markets turned positive late in the session after Democratic congressional leaders threw their weight behind a coronavirus fiscal stimulus proposal that has bipartisan support in both chambers of Congress on Wednesday. In economic reports, U.S. businesses created 307,000 private-sector jobs in November, ADP said Wednesday, marking the smallest increase in four months and suggesting a record increase in coronavirus cases has hurt hiring. Markets have mostly been trending higher on the back of vaccines to fight COVID-19. That said, an account of business conditions from the Federal Reserve's business districts, the Beige Book, indicated that worry about economic expansion without fresh economic relief was weighing on activity.