Papa John's International faced intensifying legal and investor pressure on Saturday as multiple US law firms announced securities fraud investigations following a 17.18% single-day share collapse. The Louisville-based chain's shares remained near multi-year lows.

The Law Offices of Howard G. Smith was among the firms investigating potential claims on behalf of shareholders who bought stock before the decline. The firms allege the company issued materially misleading statements about its financial health and franchise performance.

The share price drop followed weaker-than-expected results and cautious guidance, which rattled investors already concerned about softening consumer demand and competition in the US pizza market. Papa John's has struggled with declining same-store sales as diners trade down to lower-priced rivals and grocery alternatives.

Securities class-action announcements typically follow sharp single-day declines, as plaintiff firms seek lead-plaintiff roles. Analysts at several brokerages had already cut price targets on the stock following the results.

The legal filings add reputational and financial risk heading into the company's next earnings cycle. Papa John's has not publicly responded to the investigation announcements and is expected to address investor concerns at its upcoming quarterly earnings call.