COMBINED market share of the four biggest firms should be less than 40 per cent.

. Neither company should own 35 per cent of market.

. If the four biggest firms do have a market share of more than 40 per cent, there should be no significant barriers to entry by other companies.

. Or, there should be a reasonable chance that they will face competition from imports.

. "Noncompete" clauses limited to geographical area, and to two years, or five years for a business reliant on secret technical knowledge or know how.