(Reuters) - Mondelez International Inc (>> Mondelez International Inc), maker of Cadbury chocolate and Oreo cookies, on Tuesday added activist investor Nelson Peltz to its board in a compromise agreement that ends his campaign to have PepsiCo Inc (>> PepsiCo, Inc.) take over the company.

Analysts now expect the influential investor to separately lobby each company to improve their results.

Last year, Peltz urged Mondelez to sell itself to the beverage and snacks giant, but PepsiCo balked at such a deal.

Trian is Mondelez's fourth-largest shareholder, with a 2.3 percent stake, according to Thomson Reuters data. Trian also owns 0.8 percent of PepsiCo.

Peltz last summer said PepsiCo was at a "strategic crossroads" due to changing consumer tastes and the rising importance of emerging markets, and outlined two scenarios for improving results.

Plan A was to merge PepsiCo with Mondelez to create a larger company with one of the most valuable brand portfolios in the world. Plan B called for Pepsi to split its snacks and beverages businesses - which would allow each to focus on operational improvements.

"Given that Pepsi's not interested in Plan A, we are encouraging them to pursue Plan B," Anne Tarbell, a spokeswoman for Peltz's Trian Fund Management, told Reuters.

Peltz, 71, also has pushed Mondelez - whose performance has fallen short of investor expectations since it was split from Kraft in October 2012 - to manage its costs better, saying it could double earnings per share by doing so.

Peltz has been instrumental in numerous food and beverages mergers and divestitures at companies he believed were underperforming - including a series of deals that led to the creation of Mondelez.

Mondelez shares fell as much as 3.7 percent in morning trade on Tuesday as hopes for a deal with PepsiCo evaporated.

The shares were down 0.8 percent at $34.42 in afternoon trade on the Nasdaq, while PepsiCo shares were up 0.8 percent at $82.98 on the New York Stock Exchange.

"While this may have been disappointing for some investors, we see this as a very amicable outcome that now allows the management team and board (at Mondelez) to focus on running the business," Bernstein Research analyst Alexia Howard wrote in a note.

Adding Peltz to the Mondelez board increased its size to 12, with 11 directors independent.

The move also eliminated the risk of an expensive and lengthy proxy battle, J.P. Morgan analyst Ken Goldman said in a note.

Peltz helped orchestrate the 2008 spinoff of Dr Pepper Snapple Group (>> Dr Pepper Snapple Group Inc.) from Cadbury, Kraft's purchase of Cadbury, and the subsequent breakup of Kraft into Mondelez and Kraft Foods Group Inc (>> Kraft Foods Group Inc).

In addition to Mondelez and PepsiCo, Peltz's New York-based hedge fund's top five holdings include Wendy's Co (>> The Wendy's Co), Family Dollar Stores Inc (>> Family Dollar Stores, Inc.) and Ingersoll-Rand Plc (>> Ingersoll-Rand PLC).

(Reporting by Aditi Shrivastava, Martinne Geller and Lisa Baertlein; Editing by Joyjeet Das, Ted Kerr and Bernard Orr)

By Aditi Shrivastava and Lisa Baertlein