James Martin/CNET

Microsoft almost made one of the most colossal tech acquisitions in history earlier this spring.

Talks between the world's largest software maker and Salesforce.com, the San Francisco-based cloud-computing company, reached a serious level when Microsoft offered as much as $55 billion, according to CNBC. However, Salesforce CEO Marc Benioff wanted as much as $70 billion. Talks are said to have fallen through after hitting cost roadblocks.

Salesforce currently has a market valuation of more than $49 billion. Microsoft, which is the world's largest software maker, has more than $95 billion in cash and cash-equivalents it could have used to acquire a company like Salesforce. Rumors of acquisition talks between the two companies first surfaced last month.

Both Microsoft and Salesforce declined to comment.

Salesforce is a powerhouse company in the world of cloud computing. It was a pioneer of so-called customer relationship management, or CRM in the cloud, which companies use to help manage their sales efforts. The company this week reported $1.51 billion in revenue for its fiscal first quarter, and forecast sales for the full year could be as high as $6.55 billion. That makes Salesforce.com the most successful purely cloud-based application company in the industry. Salesforce was co-founded in 1999 by Benioff, a former Oracle executive.

Microsoft, which has seen more and more of its business shift to its Azure cloud-computing platform and cloud-based Office 365 software suite, is betting its future on services delivered over the Internet. An acquisition of Salesforce could have cemented Microsoft's cloud business. The deal was considered far more likely since Microsoft CEO Satya Nadella took control 18 months ago. Nadella and Benioff have notably approved of one another's leadership and have been working to repair their once-bitter relationship.

Tech acquisitions are becoming increasingly more expensive. Facebook for example, grabbed headlines with purchases of photo-sharing app Instagram for around $1 billion, virtual-reality startup Oculus VR for $2.5 billion, and chat app WhatsApp for more than $19 billion.

A Microsoft-Salesforce deal would have been among the largest tech acquisitions ever, and Microsoft's largest ever following its 2011 purchase of video-calling company Skype for $8.5 billion. Under former CEO Steve Ballmer, Microsoft tried and failed to acquire Yahoo in 2008 for $45 billion.

The honor of the biggest tech acquisition in history belongs to the AOL-Time Warner merger announced in 2000. The original purchase price was for $162 billion, but AOL's declining share price capped the deal at $106 billion when it was completed in 2001.