China’s no. 1 manufacturer of eReaders is writing a memorable tale of its own this year as brisk sales fuel profits and the wealth of its main owners.

Hanwang Technology, which also goes by the name Hanvon Technology, said today net profit in the first six months of the year more than quadrupled to 87 million yuan, or $12.8 million, from 21 million yuan a year earlier. Sales climbed to 674.4 million yuan from 176 million yuan.

Shares in the company, which went public in China this March at a IPO price of 41.9 yuan each, as of yesterday had climbed by more than two and a half times to 108.51 yuan per share, making the stake of chairman Liu Yingjian and his wife Xu Dongqing worth 4.2 billion yuan, or $618 million.

China’s eReader market will be the world’s largest by 2015, according to research firm Display Research. Hanwang had a 66% market share in the first quarter of 2010.

Its stock isn’t a bargain: yesterday’s closing price worked out to a price-earnings ratio of 101, according to Bloomberg.

China’s eReader market attracted a new competitor earlier this month when online gaming and publisher Shanda Interactive introduced an eReader called “Bambook,” which can tap into Shanda’s large collection of e-books. Amazon hasn’t launched Kindle in China.

Hanwang’s suppliers include U.S. semiconductor design house Marvell Technology.