(Bloomberg) -- Zillow Group Inc., the online real estate giant, is borrowing $450 million through mortgage bonds backed by collateral from the company’s nascent home-flipping business.

Zillow initially planned to borrow $300 million, but upsized the offering due to investor interest, according to people familiar with the effort. The company can recycle capital from the offering for up to two years as it buys and sells homes, said one of the people, who asked not to be named because the matter is private.

A representative for Zillow declined to comment.

The deal represents the first securitization by a group of next-generation home-flippers, known as iBuyers, and will enable Zillow to buy and sell more homes. It comes during a real estate boom that has created heavy investor demand for exposure to the U.S. housing market.

Credit Suisse Group AG, Goldman Sachs Group Inc. and Citigroup Inc. were the bookrunners on the offering. Representatives for the firms declined to comment.

Zillow, led by Chief Executive Officer Rich Barton, has historically concentrated on operating consumer websites and apps that help prospective buyers browse listings. It generates most of its profit by helping real estate agents find new clients.

In 2018, the company launched the home-flipping initiative, called Zillow Offers, in a bid to get closer to sellers. Zillow, famous for publishing home value estimates, uses its number-crunching prowess to make a seller an offer. When the seller accepts, Zillow buys the house, makes light repairs and puts it back on the market.

Unlike traditional home-flippers, who aim to buy low and sell high, Zillow seeks to pay a fair market price and profit by charging a convenience fee. The company acquired nearly 1,900 homes in the first quarter, and lost money on the business.

Read more: Why Zillow Went From Online Real Estate Ads to Flipping Homes

The new form of financing will come in handy for Zillow as it races against competitors Opendoor Technologies Inc. and Offerpad LLC to gain scale and consumer awareness. Zillow bought nearly 4,000 homes in the three months ending in June, according to property records compiled by Mike DelPrete. That would be the most the company has acquired in any quarter.

Opendoor, which pioneered the high-tech spin on home-flipping, acquired more than 7,000 homes during the same period, according to DelPrete’s data. The company, which went public at the end of 2020, has also considered borrowing in the securitization market, according to people familiar with the deliberations. A representative for Opendoor declined to comment.

(Updates with bookrunners and Opendoor.)

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