Published: Nov 05, 2012 1:39 PM EST
Updated: Nov 06, 2012 7:31 AM EST

WASHINGTON (AP) - The Supreme Court is reviewing two cases in which businesses are trying to make it harder for customers or investors to band together to sue them.

The justices heard arguments Tuesday in appeals from biotech company Amgen Inc. and cable provider Comcast Corp. that seek to shut down class-action lawsuits against the businesses.

Amgen is fighting securities fraud claims that misstatements about two of its drugs used to treat anemia artificially inflated its stock price. Comcast is facing a lawsuit from customers who say the company's monopoly in parts of the Philadelphia area allowed it to raise prices unfairly.

Last year, the Supreme Court raised the bar for some class-action suits when it sided with Wal-Mart against up to 1.6 million of its female employees who complained of sex discrimination.