BERLIN (Reuters) - Financial investor CVC is urging German state railway conglomerate Deutsche Bahn to reconsider its $16-billion sale of logistics arm Schenker to Denmark's DSV, a letter seen by Reuters showed on Wednesday, criticising underlining calculations for the deal.

"We are therefore firmly convinced that our offer is economically advantageous compared to the DSV offer, which is why we should have been awarded the contract for the acquisition of Schenker," said CVC's letter sent to Deutsche Bahn.

CVC would welcome a process based on "equal treatment and transparency", it added, indicating it would be ready to improve its offer.

A Deutsche Bahn spokesperson said the sales process was transparent, open and non-discriminatory.

"The result is clear: The successful bid in the sales process was the best in economic terms from all aspects and in line with clearly communicated tender parameters," she added.

Last week, DSV announced it would buy Schenker for 14.3 billion euros ($15.9 billion) in a deal that would make it the world's biggest logistics company.

Deutsche Bahn put Schenker up for sale last year to concentrate on its core railway business in Germany and reduce its debt.

The deal is subject to approval by the supervisory board of the state-owned company.

($1 = 0.8990 euros)