South Korea's top five conglomerates account for nearly all of the net profit made by the 30 biggest business groups, but their sales and employment are virtually at a standstill, data from a corporate analyzer showed Wednesday.

    CEO Score tracked performances of the 30 top-ranked conglomerates in the 2005-2015 period and found that the ratio of net profit for the highest five -- Samsung, Hyundai Motor, SK, LG and Lotte, rose from 59.3 % to 95.1 %. The increase in their sales over the years, however, was much smaller, from 59.2 % to 61.5 %.

    Such imbalance did not improve even when the category was expanded to the top 10. The enlarged group accounted for 98.3 % of total net profit, up from 79.2 %. Their sales increase was from 76.2 % to 80.7 %.

    The Samsung-Hyundai Motor dominance was stark. Together, they stood for more than half of the total net profit at 59.4 %, up from 35.3 %, analysis showed. In the case of business groups in the bottom 20, their aggregate net profit was about one-twentieth of that for Samsung.

    Despite the heavy tilt in profits, the proportion in the size of the workforce at the top 10 business groups fell from 73.2 % to 72.1 %. The ratio at the top five slightly increased to 57.7 % from 55 %, but it fell for Samsung and Hyundai Motor to 32.4 % from 35.5 %.

    The dominance by the big five was at the highest in 2014, when their net profit ratio peaked at 105.6 %, meaning they more than made up for profit losses by other conglomerates. Samsung and Hyundai Motor accounted for 81 percent in that year.

    SK Group showed the fastest growth in net profit during the measured period, jumping 198.8 %. CJ Group came next at 117.8 %, followed by Hyundai Motor at 110.9 %.