9.	Improvements to concession assets

As of December 31, 2015, 2016 and 2017, the improvements to concession assets are comprised as follows:

	Balance as of January 1, 2015				Additions			Divestitures		Transfers			Currency translation effect			Balance as of December 31, 2015
Investment:
Improvements to concession assets	Ps.	7,019,188			Ps.	2,278,944		Ps.	—	Ps.	368,575		Ps.	242,677		Ps.	9,909,384
Construction in-progress			203,950			609,743			—		(368,575	)		806			445,924
Total investment			7,223,138			2,888,687			—		—			243,483			10,355,308
Accumulated amortization			(2,074,707	)		(934,177	)		—		—			(52,106	)		(3,060,990	)
Net amounts	Ps.		5,148,431		Ps.	1,954,510		Ps.	—	Ps.	—		Ps.	191,377		Ps.	7,294,318

	Balance as of January 1, 2016				Additions				Divestitures			Transfers				Currency translation effect				Balance as of December 31, 2016
Investment:
Improvements to concession assets	Ps.	9,909,384			Ps.	331,044			Ps.	(436	)	Ps.	147,806			Ps.	514,870			Ps.	10,902,668
Construction in-progress			445,924				1,400,942			—				(147,806	)			8,682				1,707,742
Total investment			10,355,308				1,731,986			(436	)			—				523,552				12,610,410
Accumulated amortization			(3,060,990	)			(510,747	)		68				—				(126,197	)			(3,697,866	)
Net amounts	Ps.	7,294,318			Ps.	1,221,239			Ps.	(368	)	Ps.		—		Ps.	397,355			Ps.	8,912,544

	Balance as of January 1, 2017				Additions				Divestitures			Transfers				Currency translation effect			Balance as of December 31, 2017
Investment:
Improvements to concession assets	Ps.	10,902,668			Ps.	304,042			Ps.	(30,212	)	Ps.	746,710			Ps.	(143,440	)	Ps.	11,779,768
Construction in-progress			1,707,742				1,417,156			—				(746,710	)		(1,705	)			2,376,483
Total investment			12,610,410				1,721,198			(30,212	)			—			(145,145	)			14,156,251
Accumulated amortization			(3,697,866	)			(552,059	)		6,715				—			30,981				(4,212,229	)
Net amounts	Ps.	8,912,544			Ps.	1,169,139			Ps.	(23,497	)	Ps.		—		Ps.	(114,164	)	Ps.	9,944,022

Additions for investment and amortization of improvements to concession assets in 2015 include assets acquired as of April 1, 2015 by business combination, whose fair value at the acquisition date is shown below:

	Investment			Amortization			Net amounts
Improvements to concession assets	Ps.	2,264,602		Ps.	(462,719	)	Ps.	1,801,883
Construction in-progress			7,523		—				7,523
Total	Ps.	2,272,125		Ps.	(462,719	)	Ps.	1,809,406

During the years ended December 31, 2016 and 2017 no acquisitions of improvements to concession assets by business combination took place.

At December 31, 2015, 2016 and 2017, the net amounts of improvements to concession assets are:

Total balance as of

December 31,

2015

December 31,

2016

December 31,

2017

Net amounts:

Improvements to concession assets

Ps.

6,848,394

Ps.

7,204,802

Ps.

7,567,539

Construction in-progress

445,924

1,707,742

2,376,483

Total amounts

Ps.

7,294,318

Ps.

8,912,544

Ps.

9,944,022

Improvements to concession assets are comprised by intangible assets from additions and improvements to such assets in accordance with IFRIC 12, as well as other investments that have been carried out to the infrastructure of the airports qualifying as intangible assets, and even when they are not in committed investments in the MDP.

As of December 31, 2015, 2016 and 2017, the balance of machinery, equipment, improvements on leased buildings and improvements to concession assets includes investments pending to be paid in Mexican airports of Ps. 221,151, Ps. 441,515, and Ps. 409,271, respectively. Construction in-progress relates mainly to the rehabilitation of the runway and improvements to access roads at the Bajío airport, the expansion of the terminal building at the Guadalajara airport, the expansion of the general aviation aprons and the operational areas at the Hermosillo airport, improvements to the runways and aprons and extension of the checked baggage review system at the Los Cabos airport and improvements in operational areas and improvements of the terminal building in Tijuana airport. As of December 31, 2015, 2016 and 2017, the cumulative financial cost net amount capitalized was Ps. 186,834, in each year with a capitalization rate of 4.6%, in each year. During 2015 the Company capitalized borrowing costs of Ps. 1,037, respectively. In 2016 and 2017, the Company did not capitalized borrowing cost.