These promising growth stocks have crushed the FTSE 100 in April

Continuing a trend seen over many years, the FTSE 100 has been in great form since the beginning of April. That said, the near 6% rise in the value of the main index is nothing compared to the performance of some small-cap stocks.

Here are just two market minnows that have enjoyed very healthy gains over the month.

Ready for lift-off

EVR Holdings(LSE: EVRH) may not be a company on the lips of many investors but that looks all set to change if recent momentum continues. Its stock was already up 37% in April before today as excitement builds over the release of its virtual reality app -- MelodyVR -- that allows users to experience music concerts as if they were actually there.

The launch of this product will be followed by the release of US giant Facebook's new standalone VR device Oculus Go, on which the former can be experienced. The latter -- expected to cost $199 -- has been described by EVR's management as "the world's first 'mainstream' VR headset" (with no wires or additional hardware) and a "step-change" for the industry.

Today's news that the company has signed more agreements with record labels and music publishers representing artists such as The Prodigy and Queens of the Stone Age has only served to push EVR's share price even higher.

Commenting on this latest development, Executive Chairman Anthony Matchett stated that such agreements were "vital" to the firm's long-term success and "provide the company with even greater opportunities for content creation and exploitation moving forwards".

Given that virtual reality is yet to be fully embraced by the masses, it could still be argued that EVR's stock remains in 'high-risk punt' territory. Nevertheless, with deals/agreements already signed with Universal Music Group, Sony Music Entertainment, Warner/Chappell Music and Microsoft, the company's prospects looks pretty good to me.

Should Melody VR be positively received, EVR Holdings could be on the cusp of something very special indeed.

Another winner in the making?

Another small-cap that's had a great April is relatively-new-stock-on-the-block Sumo(LSE: SUMO) -- a development services provider to the video game and entertainment industries. While not quite as impressive as the rise seen at EVR Holdings, the company's value has increased by 28% in only a few weeks, in anticipation of -- and following -- an encouraging set of full-year figures with revenue up 27% to £30.6m, and gross profit jumping 47% to £13.3m.

2017 was a busy year for the company. In addition to its IPO in December, Sumo acquired digital art firm Atomhawk whose half-year numbers were "well ahead of the Board's expectations prior to acquisition". The former also launched the award-winning Snake Pass - it's first own-IP game.

According to CEO Carl Cavers, trading in 2018 has "started strongly", so much so that Sumo's board already expects full-year numbers to be "slightly ahead" of what the market is expecting. He went on to remark that the company would be "keen to accelerate" organic growth through the continued acquisition of firms that fit in with Sumo's strategy. A decent looking balance sheet with a £12.4m net cash position should help facilitate this.

Based on recent numbers and the fact that it operates in an industry that appears relatively immune to changes in consumer confidence, I'm optimistic on Sumo repeating at least some of the success of Keywords Studios and Frontier Developments. One to watch, for sure.

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Paul Summers owns shares in Keyword Studios. The Motley Fool UK has recommended Keywords Studios. 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.