The "All-Cash" Offer That Isn't: How Synthetic Cash Is Winning San Francisco Bidding Wars

If you have shopped for a home anywhere in San Francisco or on the Peninsula this year, you already know the punchline: cash wins. What you may not know is how many of those “cash” offers aren’t real.

A recent piece in the San Francisco Business Times gave the tactic a name that is starting to stick among brokers: synthetic cash. The idea is simple. A buyer who is rich on paper but light on liquid funds constructs an offer that looks, to the seller, exactly like a suitcase of money. No financing contingency, no lender appraisal, and a fast, clean close. But behind the curtain, the money is borrowed against a stock portfolio, vested RSUs, private company shares, or even a short-term loan from family, and then wired as actual cash at closing. The mortgage, if there is one, shows up 30 to 60 days later, after the deed has already recorded.

For sellers, the appeal is obvious. An all-cash offer skips the formal appraisal that mortgage lenders require, removes the risk that a low appraisal blows up the deal, and shortens the timeline. As one lender quoted in the Business Times put it, the goal is to show the seller the buyer is not “at the mercy of a lender.” That certainty is worth real money in a market this tight.

I’ve had first-hand experience with this myself. A few months ago, I was holding open a house in San Francisco’s Dolores Heights neighborhood, which has become one of the city’s most competitive. This was a beautiful older home but needed a significant amount of work. Buyers told me they planned to submit an all-cash, but said they might finance a loan later. They asked me if I thought they could get a loan on the house given its condition needing repairs.

Why this is happening now

The synthetic-cash trend is not really a financing story, it is a wealth story. Right now its become an AI-wealth story, but the trend has been around for a while in different forms.

San Francisco spent roughly five years as the national symbol of urban decline. That narrative has flipped hard. Fueled by the expansion of AI companies leasing space across Mission Bay, SoMa, and Hayes Valley, the city has become, by several measures, the hottest housing market in the country. The median home price crossed $2 million this spring, a record, and luxury sales have surged well ahead of the rest of the market. Compass data cited by the San Francisco Chronicle and the San Francisco Standard showed 144 homes selling for at least $1 million over asking in the first half of 2026, compared with just 8 in the same stretch of 2025. The flurry of activity is concentrated in San Francisco, with modest overflow onto the Peninsula.

The overbidding has reached levels that even veterans of the 2010s IPO boom find startling. The Real Deal, citing Compass, reported that July buyers paid an average of 26 percent over asking, described as the highest overbid ratio in at least 21 years, exceeding even the era when Meta, Uber, and Airbnb went public.

The wealth behind those numbers is unusually illiquid, and that is the whole point. AI compensation is concentrated in equity, restricted stock, and stakes in still-private companies. A buyer can be worth eight figures on paper and still not have four million dollars sitting in a checking account. Synthetic cash is the bridge between paper wealth and a signed purchase contract.

This isn’t actually new

Before going further, it is worth puncturing one bit of hype. The term “synthetic-cash” may be fresh, but the underlying maneuver, letting a buyer present a cash offer without actually having the cash, has been a productized service for years.

A whole category of companies built businesses around exactly this during the last hot market. Ribbon, Homeward, Accept.inc, Orchard, Better, and Flyhomes all offered versions of what the industry calls “cash-offer financing.” The mechanics were straightforward: the company would buy the house outright with its own money on the buyer’s behalf, hold the property while the buyer lined up a mortgage, and then sell it back to the buyer once the financing closed. Flyhomes overhauled its cash-offer product in 2021; Homie launched “Homie Cash” the same year. These programs typically charged a service fee of roughly 1 to 3 percent of the purchase price.

So the idea of decoupling the offer from the financing is not a 2026 invention. What has changed is who is doing it and why. Those earlier retail programs mostly served ordinary buyers who simply did not have liquid funds and needed a company to front the money. The synthetic-cash story unfolding in San Francisco is different in character: these are buyers who are genuinely wealthy, whose fortunes are just locked up in stock, RSUs, and private shares rather than sitting in a bank account. They do not need a fintech to lend them the purchase price. They borrow against their own assets, or bridge with family money, and self-fund the cash close. Same optics to the seller, but a very different buyer.

That distinction matters because it tells you something about the durability of the trend. Cash-offer financing companies rose and fell with the broader market and with interest rates. The San Francisco version is tied to a specific, concentrated pool of AI-driven paper wealth, which is a different engine entirely.

The playbook

Brokers describe several variations on the theme, and it is worth understanding each because they carry different risks for the buyer:

Margin and portfolio loans. The buyer borrows against a stock portfolio rather than selling shares, which sidesteps a capital gains hit and, for some, spreads that tax exposure over multiple years. A Palo Alto broker quoted in the Business Times described clients doing exactly this, then executing a cash-out refinance later to pay down the loan.

Liquidate now, refinance later. The buyer sells investments to pay all cash upfront to win the deal, then places a conventional mortgage on the home a month or two after closing. The financing gets decoupled from the purchase entirely.

The fully underwritten file. Rather than shopping with a pre-approval letter, the buyer completes underwriting in advance, with income statements and documentation all cleared, so that the only missing variable is the property itself. When the right listing appears, the loan is lined up and already ready to go. That advance work can compress a close to 12 to 14 days. For those who are not bidding with cash (whether actual cash or “synthetic-cash”), this can be an important strategy for being competitive.

Bridging with existing equity or family money. Some buyers pull an equity line on a home they already own to manufacture cash, planning to repay it when that home sells. Others borrow several hundred thousand to a million dollars from family for a couple of months as a pure liquidity bridge.

From the seller’s standpoint, a synthetic-cash offer is indistinguishable from the real thing. However, with the scenarios described above, financing will enter the picture eventually, but the buyer has separated the financing from the purchase offer. So when you hear that nearly half of luxury sales in San Francisco close all-cash, that does not mean those buyers own their homes free and clear. It often means the mortgage arrived after the deed recorded, where no one is counting it.

What it means, and where the risk sits

That last point deserves emphasis, because it changes how we should read the headline statistics. “All-cash share” has always been a rough proxy for buyer strength and market froth. If a meaningful and growing slice of those cash deals are financed within 60 days, then the all-cash number is overstating how much of this market is genuinely debt-free. The leverage is real; it is just showing up off-camera.

For buyers, the strategy is powerful but not free of risk. Borrowing against a concentrated stock position introduces margin-call exposure if the shares fall, which is not a hypothetical concern for portfolios weighted toward a handful of volatile tech names. Betting on a future refinance assumes rates and personal circumstances cooperate. And bridging against a home you have not yet sold assumes it actually sells, on your timeline, at your number.

In the instance of a fixer like the house I held open in Dolores Heights, there is also the concern of whether a mortgage can be obtained after the fact, and if so, what the terms may be. Would the buyer be able to finance with a conventional loan, or would the condition of the property place it in the realm of a (more expensive) construction loan? That uncertainty is not insignificant.

Nationally, all-cash purchases actually hit a five-year low at the end of 2025, as softer mortgage rates and a buyer’s market elsewhere reduced the incentive to pay cash. But San Francisco and the Peninsula are running in the opposite direction. That divergence tells you this is a local phenomenon driven by a specific and concentrated form of wealth, not a broad national shift in how Americans buy homes.

The takeaway for buyers and sellers

If you are a seller in the current market, the lesson is to look past the “all-cash” label and understand the mechanics of the offer in front of you. Proof of funds, the source of those funds, and the presence or absence of a financing contingency matter more than the word “cash” on the offer summary. A well-structured financed offer with strong proof of funds and no appraisal contingency may be every bit as reliable as a synthetic-cash offer, and sometimes more so.

If you are a buyer who cannot write a genuine seven-figure check, the good news is that you are not automatically out of the game. Getting fully underwritten before you shop, lining up portfolio or bridge financing in advance, and structuring your offer to minimize contingencies can put you on much closer footing with the cash crowd. The bad news is that everyone else with a good broker is doing the same thing, which is precisely why overbids keep climbing.

And if you don’t happen to be sitting on a pile of AI equity to borrow against, remember that the packaged version of this strategy still exists. Cash-offer financing programs from companies like Flyhomes, Homeward, and others will effectively front the purchase price so you can present as a cash buyer, then convert to a conventional mortgage after closing, usually for a fee in the 1 to 3 percent range. These programs are worth understanding as a tool, but read the fine print carefully: the fees, the repayment mechanics, and the requirement to disclose the arrangement to the seller all matter, and the economics only make sense when the competitive edge is genuinely worth the cost. For many San Francisco and Peninsula buyers up against cash, that math can pencil out. For others it is an expensive way to win a house you might have gotten with a strong, clean financed offer anyway. That is a conversation worth having with your agent before you commit.

The synthetic-cash era is, in the end, a story about a market where the appearance of certainty has become the scarcest and most valuable commodity of all. For now, the buyers who can manufacture that appearance are the ones taking home the keys.

Disclaimer: This piece is commentary and does not constitute financial, tax, or legal advice.