Marketo is for sale. Here's who may step up to buy it.

Shares of the cloud-based marketing software company Marketo rose by more than 25 percent yesterday after a report said the company is looking at selling itself.

Marketo, which has been publicly held for about three years, has been a consistent subject of M&A speculation. With a market cap of about $1.5 billion after the news, it's not that large and would probably make a sensible target for a larger company. Here are a few potential buyers.

SAP

The German software giant is the leader in an important market segment known as Enterprise Resource Planning, essentially the software that large companies use to run their operations from beginning to end. But over the last several years, it has also acquired different cloud software companies — Concur in 2014, Ariba in 2012 and SuccessFactors in 2011 — that have formed the core of a new and growing business of selling applications as a service. Marketing is one key hole in its portfolio. When Oracle and Salesforce.com were rolling up marketing application companies — Oracle bought Eloqua and Responsys, while Salesforce.com bought ExactTarget and Buddy Media — SAP was more or less out of the M&A game and gearing up to launch its HANA/S4 database. It has nearly 6.1 billion euros (about $7 billion) on its balance sheet, and along with Microsoft is one of the two leading contenders in a potential deal.

Microsoft

Microsoft is one of Marketo's largest customers, and Marketo's software has been tweaked to work directly with Microsoft's Dynamics CRM, its customer relationship management application that competes — kind of — with Salesforce and Oracle. Last year Microsoft seriously explored acquiring Salesforce itself in what would have been a massive deal worth north of $40 billion. And while its Office 365 is arguably the most widely used cloud application in business, it would like to expand its reach with more cloud-based applications. With $105 billion on the balance sheet, the purchase price would be trivial. Plus Microsoft could easily grow Marketo's business, given its large scale and reach with enterprise companies plus its Azure cloud infrastructure.

Adobe

Adobe has assembled a series of acquisitions — starting with the $1.8 billion buyout of Omniture in 2009 — in what it now call its Marketing Cloud. The most recent came earlier this month for privately held Livefyre, a service for managing user-generated content. It will be in the running, but outside of Omniture, it has shown less of an appetite for billion-dollar deals over the last few years. Its $4 billion in balance sheet cash will also be a big factor.

Google

In March, Recode reported that Google was contemplating a series of deals aimed at buying some cloud software companies that would boost its reach with mid-market business customers and enhance its overall cloud software and infrastructure business. Marketo fits the bill, reaching both large and mid-market customers, but is probably a bigger target than Google is willing to contemplate.

Oracle

Oracle took a serious look at Marketo in 2012 before opting instead to spend $871 million on Eloqua. Given its long aggressive history of software acquisitions, it will certainly be approached by Marketo's bankers at Morgan Stanley, but the meeting will be a short one.