Wall Street was up at midday on Wednesday, with the Dow Jones Industrial Average 0.32 percent higher to 12,573.46, the Nasdaq Composite up 1.09 percent to 2,457.80, and the S&P 500 adding 0.41 percent to 1,433.79. Positive earnings reports from both Yahoo and Sun Microsystems helped the gains, while the previous evening’s State of the Union address from President George W. Bush didn’t seem to have much impact at all on investors’ activities.

After Mr. Bush proposed an expansion in health care coverage in the speech last night, health benefits insurer Aetna dropped 47 cents to $41.71. In a related sector, drug maker Pfizer added 22 cents to $26.59.

ExxonMobil dropped 22 cents to $74.26 after an announcement of higher crude oil, gasoline, and distillate inventories again last week. Alternative energy producers were lower as well, after posting gains before the president’s address. Ethanol maker Xethanol Corp. dropped 17 cents to $2.90, while Archer Daniels Midland fell $1.06 to $31.57.

Sun Microsystems added 43 cents to $6.09 after increased revenues gave the manufacturer of server and storage products its first quarterly profit in several years. Meanwhile, Yahoo gained $2.03 to $28.99 on fourth quarter profits that were higher than had been anticipated. But Advanced Micro Devices dropped $1.39 to $16.12 reported losses in the fourth quarter, which were blamed on flat sales of server chips.

Wall Street was higher at midday on Thursday despite major declines in the health insurance sector. The Dow Jones Industrial Average was 0.7 percent higher at mid-session to 11,174.87, while the Nasdaq Composite had gained 0.5 percent to 2,081.01 and the S&P 500 was up by 0.4 percent to 1,272.92.

Semiconductors were higher, with National Semiconductor 4.8 percent higher to $22.55 and Broadcom gaining 4.9 percent to $23.04.

Cable tv provider Comcast added 5.3 percent to $34.25 after it reported that profits were up 7 percent in the second quarter and it upped its subscriber growth forecast for the year.

Symantec was up 10.3 percent to $17.42 even though the maker of anti-virus software reported that its profits were down by 52 percent in its first quarter, with operating expenses more than doubled. The gain came because the results were better than had been expected.

Health insurer Aetna dropped 19.8 percent to $32.03 on a 1 percent decline in earnings in the second quarter, but even more due to investor concerns about large claims on its Stop-Loss product. The rest of the sector was also lower. Cigna fell by 7.1 percent to $96.81, while Humana was 4.5 percent lower to $53.97 and United Healthcare dropped 4.2 percent to $48.43.

Dow Chemical was down 9.6 percent to $33.70 after it reported that second-quarter earnings were 19 percent lower because record revenues had been offset by higher prices for fuel.