Affirm revealed its IPO paperwork. Here's a look inside the buy now, pay later frenzy, the new twist on financing that is a must have for everyone.

• Point-of-sale financing isn't new, but it's gotten renewed attention as a wave of startups like Affirm, Afterpay, and Klarna acquired millions of new users during the coronavirus pandemic.
• On Wednesday, Affim published its S-1, the paper detailing its planned initial public offering.
• These fintechs offer consumers the ability to buy now, pay later, both online and in-store.
• And now, incumbents like Amex, Citi, and PayPal are leaning in on this new way to pay, which consumers have flocked to as a way to stretch their dollars.
• Fintechs are trying to establish their own brands, while incumbents are banking on their existing consumer base to take market share from the startups.
• Here's a look at some of the key moments over the last several months as the buy now, pay later space continues to heat up.

Point-of-sale financing has been around for a while. From in-store layaway to store-branded credit cards, retailers have always used financing as a way to convert browsers to buyers.

But over the last several years, a cohort of fintechs have cropped up offering a new way for retailers to boost sales: buy now, pay later. From no-interest, two-week installment plans to longer-term financing, fintechs like Affirm, Afterpay, and Klarna, to name a few, have won over millions of consumers and tens of thousands of retailers with their digital-forward, easy-to-use alternatives to credit cards.

Wednesday marked another big step for the market. Affirm published its Form S-1, the document detailing its planned initial public offering.

Among the revelations from the document, the fact Peloton represented roughly 28% of its total revenue for the most recent fiscal year.

Affirm's total revenue jumped to $509.5 million in the fiscal year ending on June 30, up from $264.4 million the year earlier. Affirm had a net loss of $112.6 million, slightly narrower than the $120.5 million net loss the previous fiscal year.

It's no secret that e-commerce is on the rise with continued growth year-over-year for the last decade. And like other digitally-driven trends, the coronavirus pandemic has only accelerated growth in the e-commerce segment.

In 2019, e-commerce accounted for 11% of total retail sales in the US. In 2020, total retail sales have been down, but in the second quarter this year, with brick-and-mortar retail largely shut down, e-commerce grew to 16% of total retail sales, reflecting a 44% increase quarter-over-quarter, according to the US Census Bureau.

As consumers get used to doing more of their shopping online, they're also coming around to BNPL products.

"Credit availability actually closed a great deal under pandemic conditions. So that accelerated buy now, pay later, which has emerged as the new thing at the point-of-sale, as an alternative way to actually get credit, which was important," Ben Savage, partner at Clocktower Technology Ventures, told Business Insider.

At the same time, consumer behavior, especially among younger consumers, has shifted away from credit to debit, Savage added. And these trends have proven to be tailwinds for BNPL providers, many of which have seen traction with Millennial and Gen Z consumers.

Read more: PayPal's buy now, pay later launch is kicking off the next wave of adoption. Here's what it means for startups and banks competing in the space.

BNPL has become a must-have for retailers

This time last year, online shoppers at retailers like Asos or Casper were likely to see some version of "pay in four installments" as an option at checkout, offered by fintechs like Affirm, Afterpay, or Klarna, to name a few. But today, it seems like these BNPL buttons are everywhere, becoming a must-have for e-commerce.

Over the last several months in particular, BNPL fintechs have seen explosive growth. In May, Afterpay hit five million active shoppers in the US after just two years in the market, which is now a larger market than its native Australia. The coronavirus, no doubt, has played a significant role. Afterpay nabbed one million new customers in just a ten-week span in the second quarter, when the pandemic was at its height.

Affirm and Klarna, too, have more than five million users.

Fintechs, who have spent years acquiring customers, are now looking to build brand stickiness with their own apps and loyalty programs.

Incumbents like PayPal and American Express, well-equipped with brand awareness and loyalty, are leaning in with their own versions of a point-of-sale financing product.

While BNPL products from fintechs and incumbents vary slightly on interest, fees, and credit decisioning, one thing is clear: consumers are looking for ways to stretch payments over time, even on small purchases.

What remains to be seen is where the industry will go next. For now, retailers are entering into exclusive deals with BNPL fintechs, paying them fees around 3% to 6% for each transaction. The promise of BNPL is to increase order values and the likelihood an online shopper actually buys. Those economics may be compelling in a time when total retail spending is down and advertising budgets are tight.

But traditional players like PayPal are offering buy now, pay later features at no additional cost to retailers. And with many credit-card companies, like Citi and American Express, installment financing options happen post-transaction, so merchants are just paying the typical payments processing fees.

"The economics shifted a bit," Savage said.

With many BNPL players, offering point-of-sale financing becomes a cost to merchants. Merchants could offer their own financing options like branded credit cards, but the cost to build and maintain that financing could be prohibitive for smaller retailers, even if they earned revenue from the book of credit.

"The merchants are essentially now paying in a way that really was not part of point-of sale finance 10 years ago. Or, to the extent merchants paid for it 10 years ago, it was all done through a promotional discount," Savage said.

As point-of-sale financing grows in popularity in the way credit cards did, merchants may not longer be willing to pay those fees.

Be it through higher prices on the goods sold or a surcharge at the point of sale for using a BNPL solution, merchants could start to reconsider the way they manage the cost of offering these services.

"If you play the movie forward five years and everything goes to buy now pay later, and let's say it all still looks to the consumer like a roughly zero interest rate thing, someone is paying the cost of the money. If it's the merchants paying the cost of the money, it's going to show up in higher prices someway," Savage said.

Here's a look at some of the key moments in the BNPL space over the last several months:

March

• Afterpay reaches 3.6 million active users in the US (where it launched in 2018), surpassing its native Australia in terms of user count.
• Ant Financial buys a minority stake in Klarna.

April

• Goldman Sachs' consumer bank, Marcus, partners with JetBlue to offer a buy now, pay later option on flights.

May

• Tencent buys a 5% stake in Afterpay, signaling the Australian fintech's ambitions in China. E-commerce is forecasted to account for around 40% of total retail sales in China in 2020, according to eMarketer.
• QuadPay partners with buzzy fintech Stripe to launch its card-issuing platform, enabling shoppers to use QuadPay in-store.
• Afterpay hits five million active shoppers in the US after just two years in the market.

June

• Affirm launches a high-yield savings account, playing on both the spending and saving side of its users' finances.
• Australian buy now, pay later player ZipCo acquires QuadPay in an effort to expand into the US market.
• Splitit partners with Mastercard to expand its reach in Australia, Canada, and the UK.
• Klarna launches a loyalty program for its users, part of a larger strategy to become shoppers' go-to app.

July

• Afterpay launches its in-store payments for its US shoppers via Apple Pay and Google Pay.
• PayPal rolls out its Pay in 4 product in France, a preview of its similar product roadmap in the US.
• Affirm becomes Shopify's exclusive partner for its buy now, pay later solution it offers to Shopify's US-based merchants.
• Afterpay launches a loyalty program where shoppers earn points for on-time payments.
• Sezzle raises $55 million in post-IPO equity.
• Affirm, backed by Andreessen Horowitz, Lightspeed Venture Partners, and Morgan Stanley, is reportedly eyeing a $10 billion IPO.

August

• American Express expands its Pay It Plan It and Pay Over Time products to its Green, Gold, and Platinum cards.
• Citi adds its Flex Pay product to Amazon's point of sale.
• Mastercard's Vyze, which offers retailers the ability to provide point-of-sale financing from multiple sources, adds Ally Bank and QuadPay as lending partners.
• Splitit raises $100 million in post-IPO equity from investors including Woodson Capital Management.
• Afterpay launches in Canada and acquires European buy now, pay later player Pagantis.
• PayPal rolls out Pay in 4 to all its US merchants that offer PayPal as a way to pay.
• Mitsubishi UFJ Financial Group (MUFG), one of Japan's largest banks, buys a 5% stake in Afterpay.

September

• Sezzle partners with Marqeta to launch its card-issuing platform for in-store use of its point-of-sale financing.
• Private-equity firm Silver Lake is reportedly leading a group investing $650 million into Klarna, according to The Wall Street Journal.
• Affirm raises a $500 million Series G led by GIC, a returning investor, and Durable Capital Partners LP. It also launches an interest-free bi-weekly financing option.
• QuadPay raises a $200 million line of credit from Goldman Sachs.

October

• Klarna signs 5-year contract with Macy's as its exclusive buy now, pay later partner. Macy's also invested in Klarna.
• Affirm announces it had confidentially filed with regulators for an initial public offering.
• Etsy adds Klarna as its buy now, pay later partner for purchases between $50 and $10,000.

November

• JPMorgan Chase launches a buy now, pay later option for its credit card customers.
• Affirm becomes payments giant Adyen's buy now, pay later partner.
• Affirm publishes its Form S-1.
• Quadpay is the first buy now, pay later player to launch a Chrome extension.
• Klarna hits 11 million customers in the US, with 2 million monthly active users.