It was the perfect start to the week, if you're an optimist that is, with the broad-based S&P 500 (SNPINDEX:^GSPC) hugging a tight daily range but holding on to its steady gains all day.

The interesting part about today's move higher was that it was made despite no important economic data releases at home or abroad. Instead, investors focused on a wave of merger and acquisition activity that occurred over the weekend across a number of sectors. In addition, though we're extremely early in earnings season, a number of companies that have reported have topped estimates signaling that the polar vortex is clearly in the rearview mirror and that there is no endemic slowdown in U.S. growth prospects.

By day's end, the S&P 500 had finished higher by 9.53 points (0.48%) to close at 1,977.10.

Source: Kandi Technologies.

Leading all stocks to the upside today was China-based electric-vehicle and all-terrain vehicle manufacturer Kandi Technologies (NASDAQ:KNDI), which vaulted higher by 26.6% after announcing that it had sold 4,114 electric vehicles, or EVs, in the second quarter. Comparatively, that's a 238% increase from the 1,215 EVs it sold in the first quarter. As Kandi's CEO notes, "We have not only achieved success in implementing the Hangzhou Public EV Sharing System, or the 'Carshare' Program, but also in growing our group leasing model."

While these numbers are an absolute blowout for Kandi based on what investors had been expecting, and the business model makes a lot of sense on paper considering the need for low- or no-emission alternatives for some of China's highly polluted cities, I still remain somewhat skeptical. Specifically, I worry about Kandi's ability to keep up with competition that has deeper pocketbooks, such as Tesla Motors. For the time being, I remain a bystander on Kandi.

The other two big gainers for the day come from the same deal announcement: AECOM Technology's (NYSE:ACM) agreement to purchase engineering and construction firm URS (NYSE: URS) for roughly $4 billion in a combined cash and stock deal. If you include debt the deal is valued at closer to $6 billion. All told, URS stockholders, who saw their shares rise by 12.3% today, will receive $33 in cash and 0.734 shares of AECOM stock for each share they own – which is good news because AECOM shares vaulted higher by 10.1% as well.

Source: Nuclear Regulatory Commission, Flickr.

The deal would appear to make sense on a number of fronts for AECOM. It'll allow the combined entity to be more competitive on a global scale for projects in rapidly growing Asia, it'll further expand AECOM's footprint in the energy and construction sectors, and it gives AECOM access to URS' U.S. government contracts which accounted for around a third of its revenue last year. In other words, AECOM's revenue stream just got a whole lot safer and its global growth prospects appear to have improved due to the new size of this combined company. Although I'm a bit reluctant to suggest investors consider the idea of chasing shares higher here, over the extreme long run there's little reason to believe that AECOM shares couldn't head even higher.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.