A financial technology provider has increased its damages claim against the operator of the Australian share market to $464.7 million and says the case challenges ASX’s suitability to run a market.

iSignthis raised its claim in the Federal Court by $264 million due to ASX Limited’s continued suspension of trading in the former’s shares since October last year.

The market operator earlier this year said volatile price movements and talks with the Australian Securities and Investments Commission prompted the decision.

ASX Limited has said it will defend the proceedings.

iSignthis’ initial claim of $264 million alleged misleading and deceptive conduct by ASX. The additional claim of $200.7 million is for damages from the prolonged suspension of share trading.

iSignthis chief executive John Karantzis said the impact of any adverse finding would challenge ASX’s conduct and suitability to operate a market.

He said ASX had to substantiate its reasons for the suspension.

Mr Karantzis said he and his colleagues had seen no evidence of an investigation into price volatility.

The company, which is worth $1.17 billion, listed on the Australian and Frankfurt stock exchanges in 2015.

Shares in iSignthis last traded in October for $1.07 per share.

ASX shares were trading higher by 3.11 per cent to $89.84 at 1537 AEST.