* Pepper had already agreed to KKR offer in August
* Biggest shareholder Perpetual complained deal undervalued
* KKR adds 10-cent special dividend, Pepper shares surge 4.6 pct (Recasts and adds deal value, Perpetual comment)
By Byron Kaye
Sept 25 (Reuters) - KKR & Co LP has added a small sweetener to its bid for Australia's Pepper Group, caving to a demand from the non-bank lender's biggest shareholder and bringing the deal value to A$682 million ($543 million).
With the new offer, which sent Pepper's shares surging, the U.S. buyout firm gains a slice of Australia's A$1.7 trillion mortgage market while investors will be able to cash in at a 42 percent premium to its IPO price two years earlier.
KKR announced a special dividend of 10 cents per share on Monday - appeasing Perpetual Investments Ltd, Pepper's top shareholder with a 14.7 percent stake, which had said it was unhappy with the A$657 million offer the lender had agreed to in August.
"It's clear we were vocal, that we felt the initial bid undervalued the company," said Anthony Aboud, a portfolio manager at Perpetual.
"This has been a decent investment for us. KKR have got it at a decent price and we've been trying to get as much as we possibly could."
Pepper shares rose 4.6 percent to A$3.66 by mid-session, just below the sweetened offer price of A$3.70. That compares with its 2015 IPO price of A$2.60.
Pepper's loan book jumped 36 percent in 2016, compared with the banking sector's 6.5 percent credit growth, as big banks backed off riskier lending in response to regulators' concerns about ballooning household debt.
Although the non-bank lender is seen as exposed to a possible housing correction, Australians are generally viewed as good creditors who will cut back elsewhere to meet their mortgage payments.
Pepper's shareholders will vote on the increased offer at a meeting on Nov. 15.
$1 = 1.2560 Australian dollars Reporting by Byron Kaye; Additional reporting by Hanna Paul in Bengaluru; Editing by Stephen Coates and Edwina Gibbs