DX Group, the parcel delivery and logistics firm, said City of London Police will not launch a full investigation following allegations against the company's document delivery service.
The firm said the police force's economic crime directorate would not press ahead with an in-depth probe into DX Exchange after considering the allegations made.
DX said it had co-operated with the preliminary investigation and made changes to the "internal business processes" of the operation, which will remain under review.
A spokesman at City of London Police said: "After careful consideration we have concluded that we do not consider it is in the public interest to progress to a full investigation.
"We continue to work with DX management to highlight our concerns over a number of business processes within the lower levels of the company".
According to DX Group, DX Exchange is the legal sector's "preferred document delivery service" with more than 25,000 members throughout the UK and Ireland.
The operation provides a next-day document delivery service and marketing mailshots to organisations within the network.
The update comes as the logistics firm remains in the midst of a £40 million merger with Menzies' distribution unit, an arm of John Menzies.
Following the announcement of the police's preliminary investigation, John Menzies said it would "consider its position" on the deal.
The tie-up has also come under pressure from activist investor Gatemore, which only dropped its opposition to the merger last month after the pair revised terms.
Shares in DX have been suspended since March, when news of the proposed tie-up was announced.