An index of Colorado stocks fell this week, led by Red Robin Gourmet Burgers Inc. and Apartment Investment & Management Co.

The Bloomberg Rocky Mountain News Index, a price-weighted index of companies based in the state, lost 2.48, or 0.6 percent, to 392.35.

Forty-five stocks advanced, and 65 declined.

Red Robin, a Greenwood Village-based restaurant chain, fell $2.48, or 6.5 percent, to $35.90. Apartment Investment & Management Co., a Denver-based -real estate investment trust that owns multifamily apartments, lost $2.37, or 4.1 percent, to $55.04.

Ascent Solar Technologies Inc., a Littleton-based developer of thin-film solar technology, almost doubled, adding $3.91, to $8.09.