* IPO priced around middle of its indicative range
* Aimed at complying with anti-trust rules, expanding client base (Adds IPO ranking, company performance)
By Joyce Lee
SEOUL, July 6 (Reuters) - Innocean Worldwide Inc, an advertising affiliate of Hyundai Motor Co, said its initial public offering raised $300 million, becoming South Korea's second-biggest IPO of the year.
Some 60 percent of the share sale came from shareholder Chung Eui-sun, the heir apparent of the Hyundai Motor Group, and his sister as the firm sought to comply with new anti-trust regulations by slashing the family's combined holding to just under 30 percent from 50 percent.
New laws that went into effect this year stipulate that South Korean companies in which family ownership exceeds 30 percent will be fined if they make 'unfair profits' from deals with other affiliate firms.
The IPO priced at 68,000 won per share, around the middle of an indicative range of 64,000 to 71,000 won per share and valuing the company at around 1.36 trillion won ($1.2 billion). It will make its debut on July 17.
The rest of the funds raised will go to Innocean which is looking to acquire other companies to diversify its client base, Innocean CFO Yoon Seok-hun told reporters last month.
Innocean, the country's second-largest advertising agency after Samsung Group's Cheil Worldwide Inc, garnered about 70 percent of its revenues last year from Hyundai Motor and sister firm Kia Motors Corp. It had an operating margin of 11.2 percent in 2014, compared to Cheil's 4.8 percent.
But Innocean's global advertising billing fell 7 percent over two years to 3.61 trillion won ($3.2 billion) in 2014, as Hyundai and Kia lost ground to Japanese competitors which benefited from a weaker yen.
The new anti-trust rules come amid increased scrutiny of family shareholdings in South Korea's massive conglomerates and greater calls for the interests of other shareholders to be protected.
A U.S. fund is currently challenging a proposed $8 billion merger of two Samsung Group companies seen as critical to a stable leadership transition for Samsung's founding Lee family.
Hyundai Motor also said this year it will establish a committee to represent shareholder interests when the board makes key decisions such as acquisitions, after investors were angered over a $10 billion land purchase last year that was three times the appraised price. ($1 = 1,125.5600 won) (Reporting by Joyce Lee; Editing by Edwina Gibbs)