Online-coupon phenom Groupon has tweaked its articles of incorporation to allow it to raise up to $950 million of new capital, reports VC Experts. That financing could give the Chicago-based company a post-money valuation of $6.4 billion, says VC Experts, in excess of the $6 billion reportedly offered by Google earlier this month. Groupon had a valuation of "only" $1.3 billion in its last capital raising round in April. Revenues at Groupon for 2010 are estimated at $500 million. Click for one take on what Groupon plans to do with all that money. (More Groupon stories.)