LongviewOn Tuesday, the stock market built on the gains it earned in the second quarter, with both the Dow Jones Industrial Average and the S&P 500 hitting new all-time highs. Investors celebrated continued expansion in the manufacturing sector, even though the pace of growth wasn't quite as high as they had hoped to see. Perhaps more important, market hype as the Dow approached 17,000 likely attracted typical beginning-of-month inflows from investors with automatic investing plans. In addition to those factors, company-specific factors helped send shares of 3D Systems (NYSE:DDD), Arista Networks (NYSE:ANET), and Regeneron Pharmaceuticals (NASDAQ:REGN) higher.

Ddd Cube
Source: 3D Systems.

3D Systems jumped about 6% on another strong day for 3-D printing shares, although the stock had been much higher earlier in the session. According to Bloomberg, S&P Capital IQ cited the company's decision not to attend an industry conference as suggesting that 3D Systems might be preparing itself for a bid from a potential acquirer. This is far from the first time that 3D Systems and its peers have been named as possible M&A targets, especially given the huge potential of 3-D printing as a game-changing technology for the manufacturing sector. Still, shares of 3D Systems have been extremely volatile, and until any takeover rumors actually become fact, shareholders could continue to see big moves both up and down as speculation waxes and wanes.

Arista Networks soared 22% as the newly public networking stock got a deluge of positive comments from analysts, including more than a dozen of the companies that helped underwrite the initial public offering. The more bullish analysts argued that Arista has a huge advantage over other players in the software-defined networking space, with an impressive stable of customers that include some of the largest players in social networking and e-commerce. Moreover, Arista has avoided the race-to-the-bottom mentality of some rivals, seeking to specialize to meet customer needs rather than commoditizing its business. IPO hype might well be playing some role in Arista's gains, but the company's fundamentals also show a lot of promise.

Source: Regeneron Pharmaceuticals.

Regeneron Pharmaceuticals gained 7% as Sanofi increased its stake in the company by about 2 percentage points. Going forward, Sanofi will own about 22.5% of shares, seeking to take full advantage of Regeneron's macular degeneration drug Eylea, which has been a blockbuster success and could be approved for additional indications. Regeneron does have to deal with competition from other eye-related products, but for now, the company appears to be in good shape to make the most of its opportunities going forward.

Dan Caplinger has no position in any stocks mentioned. The Motley Fool recommends 3D Systems. The Motley Fool owns shares of 3D Systems. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.