PRINCIPAL CLIENTS

3 Months Ended

Mar. 31, 2018

The following table represents revenue concentration of our principal clients:



	Three Months Ended March 31,
	2018				2017
	Revenue		Percentage		Revenue		Percentage
T-Mobile	$	18,188	27.3	%	$	22,054	28.4	%
Comcast	$	8,629	13.0	%	$	3,802	4.9	%
AT&T	$	5,070	7.6	%	$	8,647	11.1	%
Sprint	$	2,808	4.2	%	$	10,256	13.2	%

We enter into master service agreements (MSAs) that cover all of our work for each client. These MSAs are typically multi-year contracts that include auto-renewal provisions. They typically do not include contractual minimum volumes and are generally terminable by the customer or us with prior written notice.

To limit credit risk, management performs periodic credit analyses and maintains allowances for uncollectible accounts as deemed necessary. Under certain circumstances, management may require clients to pre-pay for services. As of March 31, 2018, management believes reserves are appropriate and does not believe that any significant credit risk exists.

We have entered into factoring agreements with financial institutions to sell certain of our accounts receivable under non-recourse agreements. These transactions are accounted for as a reduction in accounts receivable because the agreements transfer effective control over and risk related to the receivables to the buyers. We do not service any factored accounts after the factoring has occurred. We utilize factoring arrangements as part of our financing for working capital. The aggregate gross amount factored under these agreements was $8,749 and $28,742 for the three months ended March 31, 2018, and March 31, 2017, respectively.