More has been spent this year than in the whole of 2014.
IoT acquisitions topped $14.8 billion in the first five months of 2015, up from $14.3 billion for the whole of last year.
Buyers have purchased 39 IoT-related companies since January, less than the 62 in 2014 but with more expenditure involved.
According to 451 Research, the semiconductor market has been the main driver of spending with ARM, Intel and NXP each announcing two or more deals largely driven by IoT-related position taking.
The largest acquisition of the year so far was the $11.8 billion acquisition of Freescale Semiconductor by NXP. Other acquirers announcing acquisitions in 2015 include Amazon, ARM, Brocade, PTC, Silver Spring Networks and British Gas.
Brian Partridge, VP of the 451 Research mobility team said: "While the Internet of Things is still in its infancy in terms of industry adoption, the deal-making accelerates unabated, and we see no end in sight. The IT service and infrastructure leaders of the future will require broad and deep competencies in IoT, and those bets are being made now.
"The 2015 numbers left little time to even question our prediction that market forces would accelerate deal activity beyond 2014."