* STOXX down 0.2 pct, weekly loss of 0.5 percent
* Insurers, oil lead losses
* Technology stocks Infineon, United Internet, shine
* Aegon falls on lower Solvency 2 ratio (Recasts, updates prices)
By Danilo Masoni and Helen Reid
LONDON/MILAN, March 24 (Reuters) - European shares fell slightly on Friday, with eyes on a vote on U.S. President Donald Trump's healthcare bill, while technology companies outperformed.
The pan-European STOXX 600 was down 0.2 percent, and closed the week 0.5 percent lower, while Britain's FTSE 100 fell 0.1 percent.
Traders said markets could react negatively if the bill was rejected, although worries had somewhat eased.
"An eventual failure could let down investors," said LCG analyst Ipek Ozkardeskaya. "Yet it is worth noting that the major market focus is still on the fiscal plans and the Trump administration could carry on with its expansive fiscal plans regardless of a disappointment on the healthcare bill."
As caution ahead of the vote prevailed, data on Friday showing that euro zone businesses grew at their fastest pace in nearly six years in the first quarter had little impact on European shares.
The oil and gas sector index fell 1 percent, the biggest sectoral faller, tracking crude prices lower. Insurers also fell 0.6 percent.
Aegon was the top European faller, down 5.2 percent after the Dutch insurer reduced its Solvency 2 ratio, the key cash buffer required of insurers, to 135 percent from 141 percent. This was as a result of a reclassification of expense inflation risk.
"This may sound like a small technicality but we think it is disproportionately negative to Aegon's investment case," said analysts at KBW.
Meanwhile, a series of positive results releases pushed European technology stocks higher, the best-performing sector , up 1.2 percent.
Infineon was the top gainer, up 9.6 percent and hitting a 15-year high after it hiked its outlook on stronger automotive orders.
It helped Germany's DAX outperform European peers, the only major index to make gains, up 0.2 percent.
German mid-cap internet service provider United Internet was also a top gainer, up 5.6 percent after it posted results.
"We remain confident that the company is on a long-term growth track and see upside potential for this underperforming share," said analysts at Bankhaus Lampe, adding 2017 growth should be driven by mobile business.
Italian chip maker STMicroelectronics was among top gainers, up 4.2 percent. Analysts at Liberum said a new portable console from Nintendo contains a large number of STM chips, and its sales could add the equivalent of 1.3 percent growth to STM's revenues.
Semiconductor component manufacturer ASM gained 4.7 percent after the nomination of a new supervisory board member.
Reporting by Danilo Masoni, Helen Reid,; editing by Richard Lough and Toby Davis