NEW YORK (The Deal) -- Acquisitions of unicorns, or young tech companies valued at more than $1 billion, were a hallmark of 2014.

Mark Zuckerberg blew Silicon Valley's collective mind with Facebook's (FB) $19 billion acquisition of messaging group WhatsApp and then paid $2 billion for virtual reality company Oculus VR.

Google (GOOG) ran up an impressive tab with the $3.2 billion purchase of smart-thermometer maker Nest Labs Inc., and other investments spanning networked homes to spacecraft and satellites. Microsoft (MSFTpaid $2.5 billion for Minecraft game maker Mojang, while Amazon.com (AMZN) bought gaming video company Twitch Interactive for nearly $1 billion.

"A lot of those deals reflect a land grab of nontraditional programing," said Peter J Solomon banker Mark Boidman about the spate of transactions.

"You saw a lot of deals happen quickly, not necessarily out of fear or paranoia, but because there are not that many nontraditional programming models today that can aggregate an audience," he said. "You want to make sure, as a buyer, that you capture those before they are no longer available."

The pace of acquisitions valued at $1 billion and more has slowed in recent months, though the potential buyers still have the resources to pull off big deals.

The list of highly valued start-ups is also growing. Peripatetic bon vivant Mark Cuban blogged recently that the bubble forming in private tech companies is worse than the distortion of values in 2000.

Venture-capital information keeper CB Insights reported 38 new tech companies have become worth $1 billion or more in the last year, while media and tech boutique Digi-Capital included 15 newcomers on its list of mobile Internet unicorns.

SNL Kagan analyst John Fletcher suggested that the drop in activity is more of a lull than an end to the high-priced acquisitions of start-ups.

"The appetite for M&A hasn't gone anywhere," he said. "It will happen in bursts."

While M&A valuations have been lower in the first few months of this year, the number of consumer-oriented tech deals has increased. Last year 451 Research's M&A database tallied 79 consumer technology acquisitions totaling $25 billion. For the same period this year, 94 such companies have been acquired for $2.4 billion.

A year-to-year comparison is difficult, though. The acquisitions of WhatsApp, Oculus and Nest are outliers, 451 Research analyst Adam Phipps observed. "What you may perceive as a drop in activity may be that we had not yet had our outlier in 2015," he said.

Mobile gaming will be one active merger and acquisitions market. "It was the Rodney Dangerfield of mobile media just a few years ago," SNL Kagan's Fletcher said. "You can't really ignore the rate of growth anymore."

U.S. revenue from gaming titles on phones and tablets surpassed $5 billion for the first time in 2014, according to SNL Kagan. Sales grew 27%, representing a slowdown from 2013's 93% growth. Since 2006, the firm reported, mobile games have had a 38.7% compound annual growth rate.

The proliferation of smartphones has helped launch companies on the strength of a single game.

King Digital Entertainment (KING), which makes Candy Crush, is the largest mobile-game player, with more than $1 billion in U.S. sales and an estimated 495 million global monthly users. The Dublin company entered the mobile market in 2012 and has a $4.7 billion market capitalization.

Supercell Oy, purveyor of Clash of Clans, is second, with $380 million in U.S. sales last year. The Finnish company introduced its first mobile game in 2011.

"If you have a killer game, it scales really fast, whereas in 2007 even if you had a killer game, even if it scaled really fast, you topped out at 30 million or so," Fletcher said.

Supercell raised $1.5 billion in late 2013 from Japanese telecom and investment group SoftBank  (TYO). Digi-Capital valued the company at $2.9 billion in a March review of 68 mobile Internet companies worth at least $1 billion.

While Uber, with a worth of $40 billion, tops the list of firms with a high valuation, a dozen gaming companies are on the list. Gungho (TYO) is worth $3.3 billion, Digi-Capital reports, while Chinese group Ourpalm supports a $3.2 billion valuation.

Although the industry has averaged earnings before interest, taxes, depreciation and amortization, or EBITDA, margins of about 10% in prior years, Fletcher said, three hit makers -- King, Mojang and Supercell -- focus on a small number of titles and have margins above 30%.

"Mojang, Supercell and King are are examples of the next generation of these game publishers," Fletcher said.

"It's still a hits-based business like the film business," Fletcher said. "The economics are improving. The user base is huge. Those are the kinds of things that get those big tech companies excited."

"You'll continue to see activity in gaming, anything where people are spending lots of time on a screen and anything that's got original content that can aggregate an audience," Peter J Solomon's Boidman said.

Amazon.com's Twitch purchase last year from Alsop Louie Partners, Thrive Capital, Bessemer Venture Partners brought it a company whose product line straddles games and video. Twitch streams video of live games, with a small window showing the gamer at work in the corner of the screen.

Walt Disney (DIS) made an online video play last year, agreeing to pay as much as $950 million for YouTube network Maker Studios. Among the stars of Maker Studios is PewDiePie, whom the network calls "the #1 gamer in the world" on its Web site. AT&T (T) and Chernin Group committed $500 million last year to online video investment vehicle Otter Media.

"We'll continue to see both social media and nontraditional programmers roll out original content," Boidman said. For instance, LinkedIn (LNKDbought mobile-content distributor Pulse from Alphonso Labs for $90 million in 2013.

Aside from the quality of content, engineering and methods of presenting or curating media help to aggregate an audience. "For nontraditional programming to be successful, it has to work," Boidman noted.

Aside from Netflix's (NFLX) content deals with movie studios and its original programs, the company's appeal derives from the functionality and reliability of its service.

"It's not just about the content, it's about the delivery mechanism," Boidman said. Nontraditional programming has the potential to capture a larger, more loyal audience, when content providers can direct specific content to a subscriber, he added. "If you follow a YouTube channel, they send you updates of what could be interesting to you," Boidman said. "The content becomes curated for you."ties at the end of 2013.

And while technology companies are improving their products, Silicon Valley's capacity to fund deals is only growing. Moody's Investors Service analyst Rick Lane estimates that the U.S. tech companies it rates held about $610 billion in cash and liquid securities at the end of 2013. "That had increased maybe to $630 billion by June 2014," Lane said. "Preliminarily, it looks like it’s going to be a little higher yet when we tally the final numbers for 2014" through December.

The sum is more than double the $261 billion cumulative enterprise value of companies on Digi-Capital's mobile Internet unicorns list.

The catch is that many of the large tech companies have a large portion of their cash offshore. Repatriating the money to pay a dividend, buy back shares or make an acquisition in the States would incur a hefty tax bill.

"It was in the low 70% range of their cash being offshore last year," Lane said. "When we tally the numbers this year we're going to be moving towards 80%."

Tech groups may be tempted to make acquisitions abroad to avoid tax bills from repatriating cash overseas. Microsoft's purchases of Mojang and Skype fit the pattern.

About a year ago, Google seemed primed to spend heavily in other countries. In May, the Securities and Exchange Commission released a letter from the company. In response to questions from the SEC, Google wrote that it planned to spend $20 billion to $30 billion to buy "foreign targets and foreign technology rights" in "2013 and beyond."

Nonetheless, the Internet group has spent heavily in the U.S., as did Facebook and Amazon.com. The appetite for Internet properties with high-growth prospects outweighed the desire to make tax-efficient deals overseas, though Microsoft and others made international purchases.

Repatriating cash is not the only option for a tech company that wants to return capital to shareholders or make an acquisition.

"When you have that much of your cash offshore, if you want to increase dividends, make buybacks or make domestic acquisitions, you may have a dearth of domestic cash to do that," Lane said. "You'll need to raise debt in the U.S. to fund that U.S. use of cash." Qualcomm (QCOM) and Apple (AAPL), for example, have raised debt to pay dividends.

So the deals should keep rolling. "There's a lot of money sloshing around in richly funded late-stage companies and cash-rich incumbents all looking to make their play for the 'next big thing' and that almost certainly will lead to more blockbuster deals at mind-boggling valuations," said Tim Miller, 451 Research's vice president and general manager for financial markets.

Miller expects activity from companies developing technology for the "Internet of things," which ranges from home automation to wearable fitness trackers and monitors that track trucks or other vehicles.

From Jan. 1 to March 11 last year, deals in the Internet-of-things sector totaled $3.3 billion, 451 Research's M&A database shows. Transaction values more than quadrupled in the same period this year, reaching $14 billion.

Amazon.com bought Internet-of-things software developer 2lemetry in March. Other deals this year include NXP Semiconductors'  (NXPI) $11.8 billion acquisition of chipmaker Freescale Semiconductor, which aims to boost networking technology in cars, and Hitachi Data Systems' purchase of Pentaho, which 451 Research estimates is worth $530 million. Pentaho develops analytics software that Hitachi plans to integrate into its networked machines.

451 Research said that other targets could include analytics-software developer ParStream, cloud-analytics company GroveStreams and data storage, access and analysis outfit Snowflake Computing. GroveStreams founder Mike Mills said the self-funded Minneapolis company is seeking funding from angel, venture capital or private-equity investors. "An acquisition by an enterprise software provider would seem to be a reasonable strategy for most of the competitors in this space," he said in an email. "Consumer electronics companies, home automation providers, and other connected products manufacturers would also be a valuable partner for many."

Google made significant investments in the Internet of things space last year, with the acquisition of Nest and the follow-on purchase of home-monitoring camera start-up Dropcam for about $555 million

The Mountain View, Calif., company described acquisitions and other high-risk, high-reward initiatives as "moonshots" in its 2014 annual report, filed in February. "People thought we were crazy when we acquired YouTube and Android, and when we launched Chrome," Google's annual report declared.

Such an astronomical metaphor is appropriate. In addition to its networked-home purchases last year, Google bought satellite photography and data analytics company Skybox Imaging for $500 million and was part of a group that invested $1 billion in Elon Musk-backed rocket and spacecraft maker Space Exploration Technologies.

While the Space X investment may seem eccentric, it does play to Google's online roots. One of Space X's goals is to provide satellite service using satellites.

Indeed, the turf war between Google and Facebook may soon play out in orbit. Facebook acquired U.K. engineering company Ascenta for $20 million last year to deploy Internet connectivity from drones and satellites

Tech companies may be more comfortable with high-risk moon shots than companies in other sectors because of the nature of technology research and development. Failed experiments are expected as companies seek out hit products or services.

Amazon tried with poor results to crack into the smartphone market, a stronghold of Apple and Google. In a report, Macquarie Capital analyst Ben Schachter described Amazon's phone launch as part of a "great ecosystem war" between Amazon, Apple, Google, Microsoft and other players.

"Phones represent yet another front in this war," he wrote. "While Apple and [Google] are the clear leaders today, this is going to be a long, hard war with many battles across phones, [operating systems], TVs, PCs, laptops, hybrids, tablets, cars, home automation, robotics, wearables and much more."

Music presents yet another battlefield. Apple's purchase of Dr. Dre's Beats Electronics and its Beats Music streaming subsidiary increases the competition with Amazon's Prime Music and Google's Play. Indeed Google closed a deal last summer to acquire Songza Media.

Leading music companies include Spotify, which Digi-Capital values at $4 billion, and Pandora Media (P), with about a $3.2 billion market capitalization.

French online-music group Deezer is acquiring Muve Music from AT&T's Cricket Wireless unit. Rap star Jay Z bought Sweden's Aspiro, which runs WiMP and Tidal, for 464 million Swedish kronor (or $56 million).

Other competitors include Slacker Radio, which has backing from Mission Ventures, Rho Capital Partners, Centennial Ventures and Columbia Ventures, and Rdio  (RDIO), started by Skype co-founder Janus Friis.

The battle lines may be less distinct in the realm of virtual reality. Facebook's Oculus has a commercial product that taps a phone with Google's Android operating system as the screen and engine for the virtual-reality experience. A higher-end Oculus headset will work with Apple's Macs as well as with PCs.

Facebook's purchase of WhatsApp focused attention on messaging. Digi-Capital lists Snapchat, worth $10 billion, and South Korean outfit Daum Kakao, with a $6.5 billion enterprise value, as the most valuable messaging companies after WhatsApp.

The lesson from 2014 is that mega buyouts can occur in a diverse array of niches, from aerospace and home monitoring to messaging and video games.

M&A outliers have not yet emerged in 2015. But as networks become more advanced and connect an increasingly broad range of household, industrial and medical devices, there is yet more territory for the elite tech groups to claim.

Likewise, the population of start-ups with outsized valuations is growing.

Mark Cuban may be right about how precarious valuations are in the private market. As tech stock prices and cash balances rise, continued acquisitions of unicorns at fantastic valuations hardly seems a fairy tale.

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