Issue number 185 of the CIES Football Observatory Weekly Post analyses the stability of squads in 31 top division leagues of UEFA member associations. The championships surveyed are compared according to the percentage of players who joined the first team squad of their employer team after January 1st 2016.

The presence of club-trained footballers greatly varies throughout Europe. Issue number 164 of the CIES Football Observatory Weekly Post ranks 31 top division championships of UEFA member associations according to the percentage of club-trained players in squads.

Issue number 163 of the CIES Football Observatory Weekly Post presents the annual list of the most productive training clubs. At the head of the rankings for big-5 league players is Real Madrid, while Dutch side Ajax tops the table for footballers in 31 top division European championships.

Real Madrid squad members were on average recruited at the age of 22.5 years. This is the lowest figure at big-5 league level. Issue number 162 of the CIES Football Observatory Weekly Post presents the data for the 98 clubs from the five major European championships. German and English teams are over-represented in the top positions of the rankings.

Issue number 161 of the CIES Football Observatory Weekly Post compares big-5 league teams according to the number of players in their current squad signed after January 1st 2016. The best performing teams recruited fewer footballers than the less competitive ones. German champions Bayern Munich only signed two players.

Issue number 160 of the CIES Football Observatory Weekly Post presents the percentage of domestic league minutes played by national footballers* since the start of the season. At the top of the table is Osasuna (97%), while Udinese is at the bottom (1%).

Transfer expenditure at the top of the football pyramid has significantly grown in recent years. Issue number 159 of the CIES Football Observatory Weekly Post analyses the sums spent in transfer fees by big-5 league teams to assemble their current squad. In football history, no club has invested as much as Manchester United this season to make up its roster: €718 million (+€185 million compared to last season).

The 158th CIES Football Observatory Weekly Post presents the beneficiaries of transfer investments made by big-5 league clubs. Between 2010 and 2016, roughly two thirds of the fees were paid out to other teams taking part in the five major European championships. This percentage varies between 63% in Italy and 70% in England.

Issue number 157 of the CIES Football Observatory Weekly Post presents the 100 teams having generated the most income from the transfer of players to big-5 league clubs since 2010. Liverpool tops the rankings with €442 million, ahead of Valencia (€432 million), Juventus (€415 million) and Benfica (€414 million).

Issue number 156 of the CIES Football Observatory Weekly Post presents the table of clubs who spent the most on transfer fees since 2010 and in 2016. In both cases, Manchester City heads the rankings: €1 billion since 2010 and €231 million in 2016 (including add-ons). In the former table, Guardiola’s team outranks Chelsea (€871 million) and Manchester United (€841 million).

Issue number 155 of the Weekly Post presents the most profitable transfers of the summer from a selling club perspective. The highest gaps between fees paid (add-ons included) and amounts estimated via the CIES Football Observatory algorithm were measured for Gonzalo Higuaín at individual level (+ €23.8 million) and Sevilla FC at team level (+ €34.9 million).

While the transfer window did not yet come to an end, it is already possible to have a good idea of the profile of squads assembled by clubs. Issue number 154 of the CIES Football Observatory Weekly Post analyses the average age per team of players fielded in domestic league games. Up until now, the youngest team at big-5 league level is Nice: 23.3 years. Tottenham heads the English Premier League ranking.