These high flyers rose more than two-thirds over the last year. Can they keep soaring?

While the FTSE 100 and FTSE 250 have both climbed 17% since the start of May last year, this is nothing compared to the gains achieved by some individual companies. Here are just two that have outperformed both indexes over the past 12 months and could continue doing so in 2017.

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Robust performer

Shares in 3iGroup(LSE: III) are up 68% in just one year. Back in January, the investment manager -- which focuses on mid-market private equity and infrastructure in northern Europe and North America -- reported on "robust performance" during Q3 from its portfolio of companies. More recently, it announced a EUR200m investment in Hans Anders, a leading optical retailer and EUR120m investment in Lampenwelt, the largest European online specialist in the lighting space. 3i has also sold ESG, a UK based provider of testing, inspection and compliance services for £30m, representing a 23% uplift on its valuation at the end of 2016.

Despite recent performance, 3i still trades on a temptingly low valuation of just six based on expected earnings from 2017, rising to 11 next year. A sizeable net cash position is another positive, as is the huge operating margins generated by the £7.7bn cap. A dividend yield just shy of 3% -- while fairly average -- is also more than covered by profits (which can't be said for some constituents in the market's top tier).

3i reports its full-year results to the market on May 15. While management may offer a cautious outlook given the numerous political events ahead, I'd be surprised if it failed to continue delivering over the medium-to-long term.

Quality worth paying for

Veterinary specialist, CVS Group(LSE: CVSG) can more than match 3i in terms of share price performance. Priced at just under 750p last April (and dipping even lower shortly after the EU referendum), its stock has rocketed 77% over the last 12 months. Despite its heady valuation of 31 times 2017 earnings, I can see the good times continuing.

Back in March, CVS released a strong set of results for the six months to the end of December 2016. At £129m, revenue came in 28.5% higher than the same period in 2015. Although much of this was the result of the company's acquisition-focused strategy, like-for-like sales still increased by 7.2%. Adjusted EBITDA was up by 42.2% to £20.7m with adjusted earnings per share rising 46.3% to 21.5p. Thanks to a share placing, net debt dropped from £93.1m in June 2016 to stand at £68m.

Since the beginning of 2017, trading at CVS has been in line with expectations with like-for-like revenue growth for the first two months returning to "more normal levels". With the lucrative veterinary industry remaining highly fragmented, further strategic acquisitions (building on the 33 surgeries purchased since last June) appear likely. CVS's recent entry into the Netherlands also gives it a hint of geographical diversification, something that will surely become greater as the company enacts its ambitious growth plans.

Elsewhere, the intention to continue building on other parts of its business, including own brand products, out-of-hours centres and pet insurance should mean that CVS remains highly cash-generative.

True, the company won't be of interest to value hunters. The negligible 0.3% yield -- admittedly normal for firms with serious plans to expand -- won't appeal to those investing for income either.

While some may shudder at the current valuation however, I think CVS could be an excellent addition to any growth-focused portfolio.

Another great pick

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Paul Summers has no position in any shares mentioned. The Motley Fool UK has no position in any of the shares mentioned. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.