The phrase "a parallel firm" is correct and usable in written English.
It can be used to refer to a company that operates in a similar manner or industry as another company, often in a comparative context.
Example: "In analyzing the market, we found that a parallel firm has adopted a more aggressive pricing strategy."
Alternatives: "a comparable company" or "an equivalent business".
There are new industries: 700 biotechnology firms--a parallel pharmaceutical industry--employing scientists, apprentices, clerks and technicians.
The failure is matched by a parallel failure of Chinese firms to develop as multinationals.
The scrapping of roaming charges has been fiercely resisted by the mobile industry but the agreement on Tuesday comes with a carrot for the telecoms firms – a parallel deal on internet neutrality that would allow them to charge some service providers for faster connections to their customers.
There is a parallel with America, where listed firms tend to be domestically focused, whereas in Europe home markets are often too small to offer growth opportunities.
The firm also resolved a parallel action brought by the Massachusetts attorney general's office, agreeing to pay an additional penalty of about $132,000.
Bankers at Goldman Sachs have been accused of living in a parallel universe after the Wall Street firm announced it had set aside £8bn to pay its staff in 2011 – an average of £238,000 each.
His firm encourages creating a parallel market structure that companies can opt into, which will be more focused on creating revenue for research and value for the retail investor.
Mr Karzai said then that the firms had become a parallel security system and were causing obstructions to the development of Afghan government forces.
Goldman Sachs set aside $12.2bn£8bnbn) to pay its staff in 2011 – an average of $367,000£238,00000) each – sparking criticism that the Wall Street firm was living in a "parallel universe".
For the representative firm, an increase in the firm's capital stock leads to a parallel increase in its stock of knowledge.
