But now regulators are investigating whether such research has gone too far.

As a result, federal regulators and attorneys general in all fifty states are now investigating.

The company said it would wait until the French regulator investigates to decide on further legal action.

The German financial regulator investigated such suspicions last year, but said it did not have enough evidence to bring a legal case.

But regulators are investigating beyond the problems highlighted by Prudential's report.

Regulators have been investigating those business and trading practices.

Regulators are still investigating the accident, and neither they nor the company would discuss it while the inquiry is in progress.

And problems with Tyco's accounting came to light after a research firm got wind that regulators were investigating the company.

Federal prosecutors and regulators are investigating its pay practices, according to recent securities filings.

A fourth criterion a regulator must investigate is the firm's long-term stability.