Bundesliga summer 2026 transfers: the biggest signings ranked
Bayern Munich dropped €100M+, Dortmund landed an 18-year-old Greek prodigy, and Leverkusen lost their best player. Here’s every transfer that matters heading into the 2026/27 Bundesliga season.
August 19, 2026 · 10 min read
TL;DR
Bayern Munich spent more than every other Bundesliga club combined this summer, dropping €100M+ on two players while locking Harry Kane in until 2029. Dortmund responded to losing Adeyemi to Barcelona by signing 18-year-old Greek prodigy Konstantinos Karetsas for €32M – a bet on the future rather than the present. Leverkusen shipped their best player, Alejandro Grimaldo, to Atlético Madrid for ~€20M and are rebuilding on the fly. Stuttgart, last season’s runners-up, barely spent at all. The window opened 1 July and closes 31 August 2026 – three days after the season kicks off on 28 August. Here’s every signing that actually matters.
The summer 2026 transfer window was supposed to shake up the Bundesliga title race. Instead, it mostly confirmed what we already suspected: Bayern Munich are in a different financial universe from the rest of the league, and the gap just got wider.
That’s not to say the window was dull. A €32M teenage Greek midfielder arriving at Signal Iduna Park, a Spain international leaving Leverkusen for La Liga, a 23-year-old defender becoming one of Germany’s most expensive ever full-backs – there’s plenty to dig into. But the structural story of this window is Bayern, Bayern, and more Bayern.
Let’s rank the moves that matter.
Bayern Munich: the big spenders
No one else is close. Bayern’s two headline deals total €100M before a single add-on is triggered – and that’s before you factor in the contract extension for the league’s most clinical striker.
Ismael Saibari – €50M from PSV Eindhoven
Saibari signed for Bayern on 1 July 2026, completing a deal that had been brewing for months. The fee settled at €50M with up to €5M in add-ons – making him Bayern’s joint seventh most expensive signing in the club’s history. He’s on a five-year deal through to 30 June 2031, wearing the number 34 shirt.
The Moroccan winger had an excellent 2026 World Cup and was exactly the kind of profile Bayern’s sporting director Max Eberl was chasing: a proven Eredivisie creator with the pace to destabilise backlines at the highest level. PSV had been asking for a minimum of €50M throughout; Bayern initially proposed €45M plus €5M in add-ons, then met the asking price.
Our take: At €50M for a 25-year-old attacking midfielder fresh off a World Cup with Morocco, this is good value for a club at Bayern’s level. The risk is that Eredivisie form doesn’t always translate – but Saibari showed enough in the Champions League to suggest the step up won’t be a problem.
Nathaniel Brown – €50M from Eintracht Frankfurt
At just 23, Brown made Germany’s starting eleven at the 2026 World Cup. He’s signed a five-year deal at Bayern through to 30 June 2031, arriving from Frankfurt in a €50M deal.
The Athletic described the signing as “an investment in both the present and the future” – Brown’s athleticism and versatility at left-back made him one of the most coveted German defenders of his generation. He joined Frankfurt from Nürnberg in January 2024 and made 75 appearances, registering seven goals and 13 assists before Bayern came calling.
Frankfurt’s boss was reportedly “happy to have sold him” – a line that reads as graceful acceptance of the inevitable when Bayern want your best player.
Our take: This one is cleaner than it looks on paper. A Germany starter at left-back, 23 years old, locked in for five years – Brown is genuinely building-block material, not a panic buy. The fee is high but the age makes it sensible.
Harry Kane’s contract extension – until 2029, ~€25M/year
This isn’t a signing in the traditional sense, but it’s the most important piece of business Bayern have done this summer. Kane is expected to sign through 2029, earning around €25M gross per year – keeping him as Bayern’s highest-paid player and the most dangerous centre-forward in the Bundesliga.
Talks were paused during the World Cup but resumed immediately after. His current deal expires in 2027, and both sides appear motivated to get it done.
Our take: This is the most consequential deal Bayern have done all summer. Saibari and Brown are quality additions, but Kane is the reason Bayern’s attack functions at the level it does. Securing him through 2029 at 32 years old is a bet that his production holds – and given his injury record and goal-per-game rate, that’s a reasonable bet to make.
Borussia Dortmund: betting on the future
Dortmund lost Karim Adeyemi – one of Germany’s most exciting forwards – to Barcelona this summer. Their response tells you everything about where the club is in its cycle.
Konstantinos Karetsas – €32M from KRC Genk
Officially confirmed at €30M plus €2M in bonuses on a five-year deal, Karetsas is the fourth of Dortmund’s summer signings – behind Joane Gadou (RB Salzburg), Justin Lerma (Independiente del Valle), and Kauã Prates (Cruzeiro). He’s 18, Greek international, and was one of the most tracked young midfielders in Europe after an outstanding season at Genk.
Getting this deal done wasn’t straightforward. Kicker reported that BVB’s last offer was under €30M and Genk were holding firm at €35M – Dortmund closed the gap and got their man.
Threads accounts were tracking it in real time:
“Borussia Dortmund have reached an agreement to sign Konstantinos Karetsas in a deal worth €33m plus a sell-on clause. The Greek [midfielder] …”
Our take: Karetsas is the kind of signing Dortmund specialise in – young, technically excellent, not quite proven at the highest level, but with ceiling that justifies the fee. It’s not an immediate Adeyemi replacement. It’s a bet that in two years, this kid is worth twice what they paid. Dortmund have a decent track record on that front.
Bayer Leverkusen: losing the best to gain the rest
The most complicated window belongs to Leverkusen. They shipped Alejandro Grimaldo – the best left-back in the Bundesliga – and spent the rest of the window trying to fill a hole that can’t really be filled.
Alejandro Grimaldo – OUT to Atlético Madrid, ~€20M
Fabrizio Romano confirmed the move as sealed. Grimaldo signed with Atlético Madrid until 2030 (with some reports indicating 2031), reuniting with La Liga after years at Benfica and Leverkusen. Leverkusen received around €20M – surprisingly low for a player of his calibre, but their negotiating position was weak with his contract expiring in 2027.
Grimaldo had made his intentions clear. He told Kölner Stadt-Anzeiger as recently as August 2025:
“It doesn’t have to be this summer – but I have always said I want to go back to La Liga.”
Leverkusen replaced him with Miguel Gutiérrez from Napoli and added Facundo Medina from Marseille for defensive depth, plus Afonso Moreira from Lyon in attack. It’s a respectable set of additions. But the r/borussiadortmund thread put it plainly:
“Leverkusen lost their best player in Grimaldo. Dortmund have kept the squad together quite well this summer.”
Our take: Losing Grimaldo for €20M hurts. It’s arguably one of the worst pieces of business of the whole window – not through incompetence, but because there wasn’t a better outcome available. Gutiérrez is a solid replacement, but Grimaldo was elite. Leverkusen are still a top-three side; they’re just not the Bayern threat they might have been.
VfB Stuttgart: doing more with less
Stuttgart were last season’s runners-up, finishing second after a 4-2 defeat to Bayern. Their window reflects exactly where they are financially – careful rather than ambitious.
Leo Sauer – €15M from Feyenoord
Sauer completed his move to Stuttgart at the end of July, with the fee confirmed at approximately €14.9M (rising to €17M with bonuses). The 20-year-old Slovak winger is quick, direct, and adds width to a Stuttgart side that had been leaning heavily on its core to produce attacking threat.
Feyenoord’s official announcement confirmed the deal was done, and Sauer was quoted as “delighted” with the move – not the most revealing insight, but consistent with a player who sees the Bundesliga as a legitimate step up.
Our take: At €15M for a 20-year-old, this is exactly the kind of business Stuttgart should be doing. They’re not going to outspend Bayern. What they can do is find undervalued talent in secondary leagues and develop it. Sauer fits that model well.
RB Leipzig: a window to forget
Leipzig lost more than they gained, and it wasn’t close. Péter Gulácsi departed to Villarreal, Xaver Schlager moved to Nottingham Forest, and Loïs Openda – arguably their best forward – joined Juventus.
Their headline arrival was Rocco Reitz from Borussia Mönchengladbach – a solid domestic acquisition for a side now in rebuilding mode. French centre-back Maxime Estève added from Burnley provides depth, but doesn’t offset the scale of what left.
Our take: This is a rebuilding year at Leipzig. Not the worst thing in the world – they’ve done it before and come back competitive – but expectations need to be adjusted accordingly for 2026/27.
The window at a glance: what it means for the title race
With the season kicking off on 28 August 2026 – three days before the transfer window closes – the picture is already fairly clear.
Bayern enter as overwhelming favourites. That’s not a controversial take – it’s the structural reality of a club that spent €100M+ this summer while their nearest challenger lost their best player for €20M. Leverkusen remain the most credible threat, and Xabi Alonso’s system is good enough to keep them in contention even without Grimaldo. Stuttgart are the dark horse: continuity, experience, and a runner-up campaign behind them. Dortmund are in a transitional phase – watch them in two years when Karetsas matures.
The window might close with a few more moves. But the hierarchy is largely set.
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Frequently Asked Questions
Who did Bayern Munich sign in the summer 2026 transfer window?
Bayern Munich’s two headline summer 2026 signings were Ismael Saibari from PSV Eindhoven (€50M, five-year contract until 2031) and Nathaniel Brown from Eintracht Frankfurt (€50M, five-year contract until 2031). Bayern also confirmed Harry Kane’s contract extension until 2029 at approximately €25M gross per year.
How much did Borussia Dortmund pay for Konstantinos Karetsas?
Borussia Dortmund signed Konstantinos Karetsas from KRC Genk for a confirmed fee of €30M plus €2M in add-ons, on a five-year contract until 30 June 2031. The 18-year-old Greek international is one of the most exciting young midfielders in Europe.
Why did Alejandro Grimaldo leave Bayer Leverkusen?
Alejandro Grimaldo left Bayer Leverkusen for Atlético Madrid in summer 2026 on a contract until 2030 (some sources indicate 2031). Grimaldo had publicly stated his desire to return to La Liga, and with his contract expiring in 2027, Leverkusen agreed a deal in the €20M range to avoid losing him for free the following summer.
When does the Bundesliga 2026/27 season start?
The 2026/27 Bundesliga season begins on 28 August 2026, with Bayern Munich kicking off their title defence. The summer transfer window closes on 31 August 2026, three days after the season opener – meaning last-minute deals are still possible after matchday 1.
Who is the favourite to win the Bundesliga in 2026/27?
Bayern Munich are the overwhelming favourites to retain the Bundesliga title in 2026/27. As defending champions who invested over €100M in new signings (Saibari, Brown) and secured Harry Kane’s contract through 2029, they enter the season with the deepest and most expensive squad in Germany. Bayer Leverkusen, despite losing Grimaldo, are the most credible challengers, with VfB Stuttgart – last season’s runners-up – as a dark horse.