Shares in health insurance comparer iSelect have sunk by more than 15 per cent in their first day on the share market.

The 13-year-old company’s share price opened at $1.76 when it began trading on the Australian Securities Exchange at noon on Monday, below the $1.85 shareholders paid for the stock ahead of its $215 million listing.

The shares continued to fall and closed at $1.56, down 29 cents, or 15.7 per cent.

That equates to a $75 million drop in iSelect’s market value in its first four hours as a publicly listed entity.

The wider market was also lower, down by about 1.5 per cent.

IG market strategist Evan Lucas said iSelect faced strong competition from the privately-owned comparethemarket.com.au, plus the prospect of big insurers like Insurance Australia Group, AMP and Suncorp starting their own comparison websites.

“The technology that iSelect is offering is not groundbreaking and it’s not as hard as it looks,” he said.

“It does look like iSelect may struggle over the next coming months.”

Mr Lucas said low barriers to enter the insurance comparison market would have seen iSelect struggle, even on a day when the share market was rallying.

Damien Waller, the executive chairman and co-founder of iSelect, said the company’s float was a “major milestone for the company”.