• FTSE 100 down 0.1 pct
• Oil companies fall on weak US data
• IAG results disappoint investors
• RBS down on Q3 loss, faces litigation costs

LONDON: UK shares dipped on Friday, pulled lower by disappointing company results and oil companies falling after the price of crude retreated on weak US economic growth data.

The blue-chip FTSE 100 index was down 0.1 percent at 6,392.62 points at 0939 GMT, although it remained set for its best monthly performance since July 2013.

"I'm still of the theory that this is a bear market rally," Jasper Lawler, market analyst at CMC Markets, said.

"I think no one ... can confidently say that we are going to be breaking out higher into the next leg of the bull market right now, and with the uncertainty, and the fact that we've already had a good, strong move higher, leads me to think that maybe we could be about to turn down."

British oil companies led the index lower after the price of oil slipped following disappointing US economic growth figures, with the FT350 oil & gas index falling 0.6 percent.

Shares in airline operator IAG fell 4.4 percent after its increase in profit guidance disappointed investors.

"This reversion looks like little more than profit-taking off the back of the good news, but as has been noted this is a cyclical industry and how much more upside is left does present a reason to be cautious," Trustnet Direct market analyst Tony Cross wrote in a note.

Royal Bank of Scotland retreated 1.5 percent after posting a loss in third-quarter results and warning that future costs relating to litigation and past misconduct could be substantially higher than expected.

Among mid-caps, drug developer Vectura Group rose nearly 9.6 percent after the US Food and Drug Administration cleared treatments for chronic obstructive pulmonary disease.