Big investors reject sweetened $2.1 bln bid for Germany's Aareal Bank

BERLIN, Jan 26 (Reuters) - Two big investors in Aareal Bank on Wednesday rejected a sweetened $2.1 billion bid for the German lender, with one calling it "lousy" and a second saying it significantly undervalued the group.

The buyout group, which includes U.S.-based Advent International and Centerbridge Partners, earlier on Wednesday raised their offer to 31 euros per share from 29 euros, hoping to convince investors who had been unhappy with the price.

They said the new bid, which values the lender at 1.86 billion euros ($2.10 billion), was final.

In a statement Adam Epstein, co-founder of Teleios, which holds a 5% stake in the bank, called the fresh bid a "token increase".

The offer "represents a sweet deal for Advent and Centerbridge and a lousy one for shareholders, who should hold out for fair value", he said.

Petrus Advisers, which holds nearly a 16% stake, said in an email that the new bid "very significantly" undervalues the real-estate lender.

In an effort to revive the flagging deal, the buyout group last week lowered the acceptance threshold to 60% from 70% and extended the acceptance period to Feb. 2 from Jan. 19.

Aareal Bank's management and its supervisory board have supported the deal despite opposition from investors.

Shares in Aareal initially spiked on the increased offer but were trading roughly flat at midday at 27.88 euros.

($1 = 0.8847 euros) (Reporting by Kirsti Knolle; Additional reporting by Tom Sims and Alexander Huebner; Editing by Riham Alkousaa, Jason Neely and Jan Harvey)