The S&P 500 and the Dow Jones industrial average were slightly higher on Tuesday as crude rose after an oil workers' strike in Kuwait hurt output.
The Nasdaq composite edged lower, weighed by a 22 percent slide in Illumina. The diagnostic test maker's shares were trading at $138.50 after its preliminary results fell short of expectations.
Crude rose more than 1 percent, shrugging off Sunday's failed talks among producers to tackle a global glut.
A recent rebound in crude, some signs of a slow recovery in the U.S. economy and the Federal Reserve's caution over raising interest rates have helped stocks rally in the last two months.
On Monday, the Dow Jones industrial average closed above the 18,000 mark for the first time since July. The S&P 500 closed just 40 points below the record high it touched last May.
However, traders seemed cautious about the sustainability of higher oil prices.
"Really, it's like a party that's gone on for too long. It just takes one little thing to happen and the party breaks up and people run out like roaches," said Phil Davis, chief executive of PSW Investments.
At 9:43 a.m. ET the Dow Jones industrial average was up 34 points, or 0.19 percent, at 18,038.16, the S&P 500 was up 3.11 points, or 0.15 percent, at 2,097.45 and the Nasdaq Composite was down 14.52 points, or 0.29 percent, at 4,945.50.
Eight of the 10 major S&P sectors were higher, led by a 0.95 percent rise in the materials sector. Newmont Mining rose 5 percent and gave the sector its biggest boost.
While U.S. corporate earnings are seen as a swing factor for the stock market, expectations are bleak.
First-quarter earnings at S&P 500 companies are expected to fall 7.7 percent on average, and revenue by 1.3 percent, according to Thomson Reuters I/B/E/S.
Goldman Sachs shares were up 1.8 percent at $161.80. The bank's shares fell premarket after it reported a fall in profit for the fourth straight quarter.
IBM fell 4.7 percent to $145.45 after it reported its worst quarterly revenue in 14 years.
Netflix shares were down 8.3 percent at $99.41 after the video streaming service's subscriber forecast missed estimates.
Advancing issues outnumbered decliners on the NYSE by 1,951 to 693. On the Nasdaq, 1,329 issues rose and 940 fell.
The S&P 500 index showed 29 new 52-week highs and no new lows, while the Nasdaq recorded 33 new highs and four lows. (Reporting by Abhiram Nandakumar in Bengaluru; Editing by Don Sebastian)