Huge technology companies are gobbling up startups focused on the Internet of Things (IoT) at a dizzying rate, charting more than $31 billion in IoT-related acquisitions and investments between 2011 and 2015.

An article by ARN reports that data from Ovum’s IoT Investments Tracker showed tech firms spent $31 billion on 76 deals in eight sectors that include connected cars, wearables and IT Services, with many of those deals coming from industry heavyweights.

“While telcos are growing more interested in IoT, the data show that vendors like Intel and Qualcomm, and tech giants like Google, are still putting the most money into the sector,” said Francesco Radicati, a senior analyst with Ovum.

“Thanks to their corporate venture funds and their proximity to key innovation ecosystems, these firms have the expertise to identify up-and-coming IoT startups, as well as the funds needed to invest and acquire such companies.”

Ovum’s data revealed that Intel’s $16.7 billion acquisition of chipset manufacturer Altera was the single biggest deal. This was followed by acquisitions worth over $1 billion by Qualcomm, Verizon and Google between 2011 and 2015.

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Huge multinational vendors are looking to bulk up the IoT capabilities by absorbing specialist startups rather than build them from the ground up.

Telecommunications companies are becoming more active buyers, with Vodafone’s 2015 purchase of connected automobile services startup Cobra and the buyout of Hughes Telematics by Verizon in 2012.

“Telcos are becoming more active themselves, by setting up their own venture funds and startup accelerators and by making acquisitions to support their existing strategies,” said Radicati.

Over the four-year period, Ovum reported that the number of buyouts grew from four to 19. Investments into such hot IoT players as Fitbit grew over the period as well, with the number of investments peaking in 2013.

The largest single deal of 2015 was Sigfox’s $115 million series D round. In the round, the ultra-narrowband network provider attracted investment from the venture funds of SK Telecom, Telefonica and NTT Docomo.