(Sharecast News) - The FTSE 250 was down 0.16% at 19,889.05 at 1520 BST.
Kainos shares were down after analysts at Berenberg downgraded the software outfit to 'hold' from 'buy', stating the firm was now "stuck in an awkward spot".
Berenberg stated the decision to downgrade Kainos was "a difficult one" and noted that it might seem "odd" given its bullish position regarding the IT services landscape and the fact that it even thinks scope remains for the firm to outperform consensus topline forecasts.
However, the German bank said the challenge was cost inflation, which it thinks has accelerated since the first half of Kainos' trading year and with little ability to renegotiate pricing on contracts already underway, it thinks there is "a strong likelihood" that the company will rebase short-term margin guidance at a lower level.
Diploma shares fell as interim revenues missed estimates. The maker of specialist seals and medical measuring instruments said it expected annual operating margins to be at the top end of guidance after posting a rise in interim profits.
British Gas owner Centrica rose after the UK's energy regulator said it planned to introduce quarterly consumer price cap reviews, given the major suppliers a chance to hike prices faster. A move savaged by fuel poverty campaigners.
The cap, introduced in 2019 to prevent energy companies over-charging customers for gas and electricity, is currently reviewed twice a year.
At the most recent review in April, it was hiked 54% in response to the soaring wholesale energy prices. Another increase is expected in October.
A number of personal finance experts reacted with dismay to the proposed changes. Martin Lewis, founder of Money Saving Expert, tweeted: "It feels like at every turn, in these desperate times where lives are at risk, [Ofgem] has ignored all asks for consumers and instead kowtowed to the industry."
Myron Jobson, senior personal finance analyst at Interactive Investor, said: "Adjusting the cap more regularly in the current high and rising inflation environment means energy bills will go up more frequently, which could spell disaster for households already struggling to stay financially afloat.
Fintech outfit Plus500 rose after reporting that trading had continued to be "very strong" in the second quarter, with the group growing increasingly confident of its full-year performance.
As a result of its "strong performance" in 2022 year-to-date, Plus500 now anticipates that full-year revenue and underlying earnings will be "significantly ahead" of current market expectations.
FTSE 250 - Risers
Polymetal International (POLY) 254.90p 7.10%
Centrica (CNA) 80.44p 4.41%
Plus500 Ltd (DI) (PLUS) 1,574.00p 4.17%
Ferrexpo (FXPO) 153.20p 4.01%
HGCapital Trust (HGT) 404.50p 3.72%
Drax Group (DRX) 775.50p 3.47%
Apax Global Alpha Limited (APAX) 186.00p 3.33%
TP Icap Group (TCAP) 123.10p 3.19%
Hochschild Mining (HOC) 102.10p 2.72%
Wood Group (John) (WG.) 225.40p 2.59%
FTSE 250 - Fallers
Kainos Group (KNOS) 1,061.00p -6.19%
Baltic Classifieds Group (BCG) 147.00p -6.13%
Diploma (DPLM) 2,448.00p -5.99%
Network International Holdings (NETW) 214.00p -5.14%
Wizz Air Holdings (WIZZ) 2,954.00p -3.68%
Spirent Communications (SPT) 224.40p -2.94%
Morgan Advanced Materials (MGAM) 286.00p -2.89%
Genuit Group (GEN) 414.50p -2.81%
Darktrace (DARK) 384.60p -2.76%
IMI (IMI) 1,276.00p -2.60%