Wall Street closes flat

US stocks have closed flat, hovering around record highs despite a soft earnings release from Radio Shack and a decision by Botox maker Allergan to reject a takeover offer from Valeant Pharmaceuticals.

At the closing bell, the Dow Jones Industrial Average edged to its fourth straight closing high, adding 2.82 points, or 0.02%, to 16,945.92.

The broad-based S&P 500 lost 0.48 of a point, or 0.02%, to 1,950.79, while the tech-heavy Nasdaq Composite Index added 1.75 points, or 0.04%, to 4,338.00.

While the Dow continued its record streak, a late rally on the S&P 500 wasn't quite enough to see that index secure its seventh record close in just eight days.

Stock in Radio Shack sunk 10% after the long-suffering retailer said it lost $US98.3 million ($106.3m) in the first quarter amid a sales retreat of over 13% on the year prior.

Elsewhere, Botox maker Allergan spurned a revised $US53.5 billion ($57.8bn) takeover proposal from Canada's Valeant, saying the current offer "substantially undervalues" its growth prospects.

The development led Allergan shares 0.65% lower, while Valeant stock yielded 0.85%.

There was little in the way of economic data for investors to analyse overnight, leaving company news as the main driver of sentiment.

Later in the week producer price inflation, retail sales and weekly jobless claims in the US will be on tap, though it is a largely tepid week of economic news as the US heads into the slower summer season.