 Bloomberg -- Alarm.com Holdings Inc. plunged as much as 20, the most intraday in almost five years, after Alphabet Inc.s Google announced a partnership to create smart-home security products with ADT Inc.Stifel analyst Brad Reback said the pact is a potential long-term issue for Alarm.com, which offers interactive security and video monitoring for residential and commercial properties. In a February filing, Alarm.com said ADT represented greater than 15 but not more than 20 of its revenue in the three years ended 2019.This ADTGoogle partnership could become a headwind to ADTs existing technology relationship five-year deal with Alarm.com that was formed in 2017, Reback said.William Blair analyst Matthew Pfau said he doesnt expect that the alliance will have a material impact on Alarm.com over the next year, as itd be tough for ADT to move its roughly 3 million subscribers on Alarm.com to another platform. But Pfau said, at the least, the partnership could be used to put pressure on Alarm.com during contract renegotiations. As a result, Pfau downgraded his Alarm.com investment rating to market perform from outperform, also citing a lack of catalysts to lift Alarm.coms stock.Shares of home-security company Resideo Technologies Inc. also slumped Monday, falling as much as 22 in the biggest intraday decline since March.ADT expects to offer some Google devices to its customers starting this year and to expand the integration in 2021, according to a statement. As part of the partnership, Google will invest 450 million to acquire a 6.6 stake in ADT.For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.2020 Bloomberg L.P. 