Why do metasearch companies like trivago exists? Why does booking or Expedia participates in trivago auctions. I am logged in user of trivago, I still get cheaper deal for same room type and property if I go through trivago than direct search in booking. Booking already has me as customer then why are they reducing margin to get reservation from me again

What you are experiencing is a textbook example of behavioral price discrimination combined with channel-specific commission rebating. Even though Booking.com already has you as a customer, how you arrive at their checkout page dictates whether their pricing algorithm treats you as a captive buyer or a flight risk.

1. Why Metasearch Exists (And the Ownership Plot Twist)

On the surface, metasearch engines like Trivago, Kayak, and Google Hotels exist to solve distribution fragmentation. A single hotel room isn't just sold at one fixed price; its price varies across platforms due to regional promotions, currency arbitrage, loyalty tiers, and leaked wholesale inventory (rooms sold in bulk to B2B "bedbanks" like Hotelbeds or WebBeds that get repackaged online). Metasearch aggregates the aggregators.

Behind the scenes, however, the travel industry is a duopoly operating an illusion of choice:

• Expedia Group owns a majority stake in Trivago (alongside Expedia, Hotels.com, and Vrbo).
• Booking Holdings owns Kayak and Momondo (alongside Booking.com, Priceline, and Agoda).

The two giant holding companies keep metasearch brands separate to capture two distinct psychological segments: convenience shoppers (who open the Booking.com app directly) and price-comparison shoppers (who refuse to book without checking a comparison grid first).

2. Why Booking and Expedia Participate in Trivago Auctions

It seems counterintuitive that Booking.com pays money to Trivago (owned by its chief rival, Expedia) to acquire customers it already knows. In reality, Booking Holdings historically accounts for roughly 45% to 55% of Trivago’s total revenue, while Expedia Group accounts for another 25% to 35%.

They participate because of a strict Prisoner's Dilemma at the bottom of the funnel:

• High-Intent Traffic: A user on Trivago has already selected a city, check-in dates, and a specific hotel. They are minutes away from transacting.
• Zero Defection to Direct: If Booking.com refuses to bid on that hotel's auction slot on Trivago, you won't close Trivago and open the Booking.com app just to check if they have it. You will simply click the next link down—Agoda, Expedia, Trip.com, or the hotel's direct site.
• Contribution Margin over Percentage Margin: As long as the commission Booking.com earns from the hotel exceeds the Cost-Per-Click (CPC) or Cost-Per-Acquisition (CPA) fee paid to Trivago, the transaction adds net dollars to Booking's bottom line—while denying that booking to a competitor.

3. Why You Get a Cheaper Rate via Trivago Than Going Direct

When you search directly on Booking.com vs. clicking through from Trivago, you trigger completely different pricing rules—even for the exact same room, property, and logged-in account.

A. Revealing Your Price Elasticity (Channel Price Discrimination)

• Direct Traffic = Inelastic: When you open Booking.com directly, you signal high brand loyalty and low price sensitivity. Booking shows you the standard retail rate (or standard Genius tier) and pockets its full 15% to 25% hotel commission.
• Metasearch Traffic = Hyper-Elastic: When you click a link on Trivago, the referral URL appends tracking parameters (e.g., aid= or label=trivago-...). This tells Booking.com that you were just staring at a live price table comparing them against five other OTAs.

B. OTA Commission Rebating ("Sponsored Discounts")

Trivago's auction algorithm doesn't just rank OTAs by who pays the highest CPC bid; it heavily weights price competitiveness because users rarely click a higher-priced link for the identical room.

To win the top spot on Trivago when a competitor (like Trip.com or a wholesale-fed OTA) undercuts the standard rate, Booking.com uses OTA-funded discounting. Booking unilaterally sacrifices a portion of its own hotel commission to lower your checkout price—a discount it has no reason to offer when you visit Booking.com directly.

Booking makes $17 instead of $40, which is still infinitely better than the $0 it makes if you book through a competitor on Trivago.

C. Why Booking Doesn't Raise the Price Once It Sees You Are Logged In

You mentioned you are logged into Trivago and already a Booking.com customer:

1. Identity Silos Before the Click: Being logged into Trivago only identifies you to Trivago. Due to third-party cookie restrictions and competitive rivalry, Trivago does not tell Booking.com who is viewing the auction grid before you click.
2. Anti-Bait-and-Switch Enforcement After the Click: Once you land on Booking.com (where you are logged in), Booking knows you are an existing customer—but it is locked into the $185 Trivago price. Metasearch platforms run automated price-accuracy crawlers. If Booking advertises $185 on Trivago to win the click and then flips the price to $200 upon detecting your logged-in Booking session cookie, Trivago and Google Hotels will penalize Booking's quality score or suspend its auction feed for price mismatches. Furthermore, seeing the price jump would cause you to hit the "Back" button immediately.

D. Wholesale "Partner Offers" & Bedbank Routing

Frequently, clicking through a metasearch link unlocks Booking.com "Partner Offers." These are rooms sourced not from Booking's direct contract with the hotel, but from third-party wholesale bedbanks (originally intended for offline travel agents or flight-plus-hotel bundles). To prevent hotels from getting angry that their own public rates are being undercut on Booking.com's main search page, OTAs often "fence" these cheaper wholesale rates so they only surface seamlessly when triggered by an external metasearch comparison link.

The interactive simulator below illustrates how an OTA's pricing engine balances commission rebates and metasearch auction costs against the risk of losing a price-sensitive comparison shopper.