The Fortunes of MacKenzie Scott

The billionaire philanthropist MacKenzie Scott once recounted, in a television interview, a Chinese folk tale sometimes known as “The Lost Horse.” The story is about the reversals of fortune a farmer experiences after his prized stallion runs away. It can also be read as a summary of her philosophy.

“You never know where it’s going to end up. Good luck, bad luck, it’s not the way that we really need to look at things,” she told the television host Charlie Rose in 2013, after relating the parable to him.

The hardships we experience “are the things that we’ll look back and be the most grateful for,” she said during the interview. “They take us where we need to go.”

Her own life has taken sharp turns that have shaped her choices, including her extraordinary leap into philanthropy, which in under three years has exceeded $12 billion in grants.

A privileged child, she left a Connecticut boarding school after her family declared bankruptcy. In college, a loan from a friend helped keep her from dropping out. That allowed her to carry on studying creative writing under the acclaimed novelist Toni Morrison, who would become her mentor and help her achieve her own life’s goal of becoming a novelist as well.

And as a recent college graduate, working in recruitment at a financial firm, she married the man in the office next to hers, Jeff Bezos, and moved to Seattle to help him pursue his dream of an online retail empire — one that would make each of them among the wealthiest people in the world even after their marriage dissolved.

A few months after their divorce was finalized in 2019, a new shell company was quietly set up in Delaware called Lost Horse. Soon, representatives from Lost Horse were calling nonprofits around the country about multimillion-dollar donations from an anonymous giver.

The secret benefactor turned out, of course, to be Ms. Scott. Her sudden spate of giving has now reached 1,257 groups, from little-known charities to mainstream organizations like Habitat for Humanity, which last month received $436 million, her largest known gift.

The $12 billion in grants she has announced add up to more than the total lifetime giving of the late Eli Broad and his widow, Edythe, renowned for their generosity in Los Angeles, not to mention far richer couples, like Facebook’s Mark Zuckerberg and his wife, Priscilla Chan. Her ex-husband, Mr. Bezos, has pledged $10 billion to combat climate change. Forbes in January calculated that he had paid out $2.1 billion in charitable giving so far.

But as Ms. Scott’s fame for giving away money has grown, so, too, has the deluge of appeals for gifts from strangers and old friends alike. That clamor may have driven Ms. Scott’s already discreet operation further underground, with recent philanthropic announcements akin to sudden lightning bolts for unsuspecting recipients.

Attempts to reach Ms. Scott and her husband, Dan Jewett, a chemistry teacher, for this article by phone, email and letter, directly and through intermediaries, were met with silence.

Instead, The New York Times relied on interviews with more than two dozen friends, teachers, former colleagues and acquaintances from every chapter of her life, as well as public records and the rare interviews Ms. Scott has given, generally in conjunction with the publication of one of her novels. This article is also based on previously unpublished letters between Ms. Scott and Ms. Morrison, kept in the Nobel laureate’s archive at the Princeton University library.

“I guess the only way I will find out what will not work for me in life is by trying it,” she wrote to Ms. Morrison in September 1992, a few months after graduation and at a pivotal moment for her future. Waitressing in New York had proved more grueling than waiting tables in Princeton during college, leaving her too tired to write.

“I found myself with unpredictable and small chunks of time during which I either collapsed from exhaustion and frustration, or ruminated over the excruciating monotony of making and selling sandwiches,” she wrote, “and worried about how I might pay my rent with the nickels they gave me in exchange for my ennui.”

The week before, she had started work at an investment firm, with her future husband, Mr. Bezos.

Three decades after worrying about making rent, and even in the wake of her recent gifts, Ms. Scott, 52, hovers around $50 billion, according to Forbes magazine. She has set about dispersing her enormous fortune with unprecedented speed and directness to frontline charities and nonprofits with a stated emphasis on advancing social justice and combating inequality, all while trying to keep herself out of the spotlight.

“Putting large donors at the center of stories on social progress is a distortion of their role,” she wrote in an essay last year, one in a series of deliberate public communiqués on her giving.

While Ms. Scott may be seeking to stay in the background, her funds are reshaping the nonprofit sector in the United States and beyond. She has become arguably the most consequential philanthropist in the world right now — one who is very much operating on her own terms.

Her approach to public life and charitable giving has echoed her approach to storytelling. “Writing something long,” she said in the 2013 television appearance, reflecting on Ms. Morrison’s greatest lessons to her, “is all about the timed release of information.”

A born writer

Even her new last name, Scott, is one of her own choosing.

Scott was her grandfather. G. Scott Cuming was an executive and general counsel at El Paso Natural Gas, a powerful energy company that faced antitrust actions over its acquisition of a pipeline company. His wife, Dorothy, volunteered with the March of Dimes and with an organization for breast-cancer survivors.

Their daughter, Holiday Robin Cuming, was born on Christmas Day in 1943. She married Jason Baker Tuttle and the couple had three children, the eldest and youngest boys and the middle child a daughter, MacKenzie.

Mr. Tuttle worked as a financial adviser while his wife stayed home with the kids. The family had an expensive home in the Pacific Heights neighborhood in San Francisco and another house in the town of Ross, what the San Francisco Examiner at the time called “the bosky dell in Marin County for the well-to-do.”

In the afterword to her first novel, Ms. Scott tells the story of how, when she was just 6 years old, she wrote a 142-page novel called “The Bookworm,” which she described as “a chapter book about the adventures of a worm who loved to read.”

“It took me almost a year of afternoons lying on our living room carpet with a stack of Oreos, a sheaf of kindergarten newsprint, and a fat pencil,” she wrote, “and I distinctly remember the moment when it first occurred to me that I loved writing differently than I loved riding my bike or swimming.”

That same year, her mother made headlines in the local papers fighting to save neighborhood trees threatened by Dutch elm disease. One of young MacKenzie’s own first public appearances was with her fourth-grade class in December 1979 at a Ross Town Council meeting, where she presented a class project to raise money to plant a new tree.

MacKenzie continued writing and developed an early but lasting propensity for deep research. After noticing that the children’s book “Watership Down” was full of specific plant names, she “hopped on my Schwinn and rode to the library to hunt down a botanical encyclopedia, and for the next year, all my stories were stuffed with extraneous mentions of trees and flowers,” as she wrote in the afterword.

“She was infinitely more talented than anyone else in my class, and that was evident then,” said Jeff Sloan, who taught her in sixth grade. Mr. Sloan was a rigorous writing instructor who asked for weekly compositions from his pupils. Years later Ms. Scott would thank him in the acknowledgments of her first published book.

Ms. Scott’s father ran an investment advising firm called J. Baker Tuttle Corporation, which by her teenage years was paying him about $360,000, or over $900,000 in today’s dollars, according to the Securities and Exchange Commission. The firm was covering his personal and business expenses, as well as four mortgages on three properties. Ms. Scott was attending the Hotchkiss boarding school in Connecticut, while her older brother was at Georgetown University.

Classmates at Hotchkiss said they remembered Ms. Scott as disciplined about her work, gentle with others and humble in her manner. A friend from Hotchkiss, Margot Bass, described her as original in everything from how she dressed — eschewing the Laura Ashley prints many women wore on campus — to how she saw the world. The two friends painted, with Ms. Scott producing a memorable portrait of her younger brother.

Hotchkiss class of ’88

Shortly before Ms. Scott’s 17th birthday, her family’s fortunes took a sudden turn. Her father’s financial firm declared bankruptcy, and so did her parents. Ms. Scott graduated from Hotchkiss, where tuition rivaled the cost of college, after three years instead of four. In her final year, she took on extra coursework, completing a special seminar in fiction-writing arranged by the head of the English department that ensured she met the school’s four-year English requirement.

She was listed alongside the graduating seniors in the class of 1987 yearbook, and where their colleges were named it said merely that she was bound for England. “Class of ’88: I’ll miss being with you,” she wrote. “Make the most of the year, and look twice before you leave. There is so much there to see.”

Ms. Bass said she knew the Tuttles were going through a difficult time, calling Ms. Scott “beloved” and the prospect of leaving a place where she had been thriving “traumatic.”

“One thing I regret is the Hotchkiss community did not rally to support her,” Ms. Bass said. “I didn’t even know what to make of it. I was young, and I didn’t know how you support somebody whose family is going through a hard time.”

A stockbroker tried to phone Mr. Tuttle’s company in November 1987 and was told that the family was in Europe for the month, according to the S.E.C. When he called again in December the phone number was out of service, and a subsequent letter came back marked “Moved Left No Address,” according to commission documents. During what would have been Ms. Scott’s senior year of high school, ads appeared in local newspapers back in California for bankruptcy sales for J. Baker Tuttle Corporation, including items like IBM Selectric typewriters, Epson printers and mahogany desks.

With the help of a scholarship, Ms. Scott still managed to go to Princeton, albeit with a new, heavier burden. “I went off to college knowing I was going to have to work a variety of jobs to put myself through school,” Ms. Scott has said, worrying about how she was going to juggle waiting tables with a full course load.

As many other working students have found before her (and, with soaring tuition costs, even more since) it wasn’t easy. Last year, Ms. Scott recalled that period and the help she received to make it through. “It was the local dentist who offered me free dental work when he saw me securing a broken tooth with denture glue in college,” she said. “It was the college roommate who found me crying, and acted on her urge to loan me a thousand dollars to keep me from having to drop out sophomore year.”

In the meantime, an administrative law judge for the S.E.C. barred her father from associating with any investment adviser for “fraudulent, deceptive actions,” shutting the door on an easy comeback for the family’s fortunes. The administrative ruling was first reported by Medium Marker.

By the early 1990s, her parents had left behind their two houses in California and transplanted themselves to Florida, settling in an apartment building in Palm Beach where at the time units rented for around $800 a month, or roughly $1,500 today. Her mother began working at a women’s boutique on fashionable Worth Avenue a short walk away.

If this was a difficult period for Ms. Scott, it was also an intellectually rewarding one. She achieved her goal of studying creative writing under Ms. Morrison, who had recently won the Pulitzer Prize. “This writer that I admired so much also turned out to be such a gifted and devoted teacher,” Ms. Scott said. “She has given me a real example of a life of passionate devotion to more than one calling.”

The writing program was competitive. Princeton classmates recalled her as passionate about books and deeply engaged in her studies. “In the hallways she seemed introverted, but would come alive during the classroom discussions,” said Jonathan Usuka, who met her during freshman orientation and also studied creative writing.

With the sought-after prize of Ms. Morrison as her thesis adviser, Ms. Scott had written a 168-page work of fiction called “The Fathering Water,” in which the father, Luther Augery, keeps hidden that he has quit his job and settled for a low-paying one. He lies about his work and showers his wife with expensive home appliances to compensate. “He could not afford it,” she wrote, “pretending he had a job that made money and also pretending he could spend it.”

Ms. Morrison has called Ms. Scott an “extraordinary writer, almost full-blown,” and indeed the novella is strikingly assured, as well as a little bloody, macabre and almost Gothic in places. In one scene, Luther’s daughter and the undertaker’s son steal away during a wedding at the funeral home and kiss next to “the rolling shelves for storing bodies.”

After graduation, Ms. Scott went back to Hotchkiss and taught a summer creative writing program. Then, like Princetonians at least as far back as F. Scott Fitzgerald, Ms. Scott moved to New York City to pursue a career as a novelist.

Nickels for ennui

Ms. Scott found herself juggling waiting tables and writing, staying for a stint in the New York City apartment belonging to the family of her friend from Hotchkiss, Ms. Bass.

Waitressing was hard, and something was not clicking yet with her goal of writing a novel. She was invited for an interview at a hedge fund, D. E. Shaw. “I wasn’t quite ready to write a book. Truthfully it wasn’t going that well and I was having a lot of trouble making ends meet,” she said of that period. “Would I have ever considered a job in finance if I hadn’t been having those difficulties?” she asked. “Probably not.”

She was interviewed for the hedge-fund job by a fellow Princeton grad, Jeffrey Preston Bezos. In another letter to Ms. Morrison, she wrote that he hired her “based largely on a transcript of your phone recommendation.”

She settled into a routine balancing work and writing. “I’m finding I have much time to write, all in the early morning, which probably displeases the accountant who lives below me although I recently invested in a rug to muffle my 5 am trips to the kitchen for coffee,” she wrote to Ms. Morrison.

Ms. Scott landed in the office next to him. She said many times that she fell for his famously booming laugh and pursued a relationship. They dated for three months before getting engaged and were married three months after that. She was 23 and he was 29.

“He edited what was my first and, happily, last piece of financial marketing literature, and after our wedding I started working full time on a novel,” she wrote to Ms. Morrison of that period.

It was shortly thereafter that the couple entered the rarest lore of high-tech start-ups. Mr. Bezos wanted to quit his job at D. E. Shaw to take a flier on selling books over the primitive dial-up version of the internet. Given the financial instability of her teenage years, it would have been understandable if Ms. Scott had discouraged him from taking the risk. Not only did she support his dream, she worked alongside him to build the company.

“I’m not a businessperson, but to me what I am hearing when he tells that idea is the passion and the excitement,” Ms. Scott herself has said. “Couldn’t wait to hop in the car.”

The car was a Chevy Blazer, a gift from Mr. Bezos’ father. The two flew to Fort Worth, where they picked it up. Then, she drove them to Seattle while Mr. Bezos worked on the business plan in the passenger seat. They rented a house in nearby Bellevue, Wash., where Amazon was founded in the garage in 1994.

“The new news is that last July Jeff and I moved from New York to Seattle, where I’ve spent most of my time helping him start a business selling books over the Internet,” she wrote in a letter to Ms. Morrison in 1995. “Our customers can browse an electronic catalog of 1.4 million titles by author, title, subject, and keywords and place orders via computer. It’s an interesting business, and, on the whole, having a part-time job has been good for my writing.”

But she also started taking a writing seminar at the University of Washington. “Very pleasant and serious,” the instructor, Carole Glickfeld, recalled in an interview. “She really wanted constructive criticism.”

Friends remembered the couple as fun loving, big on books but also other forms of culture. At one point they paid for 50 friends to take part in a scavenger hunt at the Metropolitan Museum of Art for Mr. Bezos’ birthday.

Amazon was Mr. Bezos’ dream, and Ms. Scott did not give up on her own dream of writing novels. She left the company, making appearances at holiday parties and summer picnics, and began working on her fiction full time again. Mr. Bezos later said he would find her writing in hotel bathrooms when he woke up on vacation. She finished a draft of her first novel as her due date for their first child approached.

“You should know that I don’t feel I got there,” she wrote to Ms. Morrison in 2000. “But I do feel I got to a point well-suited to some perspective-fostering maternity leave and a dose of serious criticism from willing readers.”

She continued sending drafts to Ms. Morrison, thanking her every time for reading the latest version, and she kept up with a family tradition of sending annual Thanksgiving cards. “As you revise, I am at your service if, and only if, you want me to be,” Ms. Morrison had written in a three-page typed letter of suggestions for her manuscript, a copy of which is in her archive at Princeton. She said that she was usually glad not to have to line edit for a living anymore. “But then, then … there’s a writer out there named MacKenzie and the profound pleasure of editing comes rushing back.”

Ms. Scott’s first book, “The Testing of Luther Albright,” based in part on her undergraduate thesis about Luther Augery, took her close to a decade to complete.

She had distinct advantages over other first-time authors when the novel came out in 2005. Now a Nobel laureate, Ms. Morrison connected her own powerful agent, Amanda Urban, with her mentee and even gave her a coveted blurb for the cover of the book.

Her husband was by then one of the most famous men in America, but he was best known at the time for destabilizing the staid publishing industry to the detriment of local bookstores. Many in publishing were resentful.

Promotion and public events also did not come easily to Ms. Scott. “I am not a natural for big groups because I am such an introvert,” she told the Seattle Post-Intelligencer. “I had that feeling of stage fright before a firing squad for my first reading.”

Another hallmark of Ms. Scott’s personality on display in her writing life was her dedication to intense research. Like the child riffling through the botany book for plant species, she reached out to a plumber to understand her protagonist’s home repairs and spent time with an engineer to grasp the details of his work building dams.

There was also a nascent sense in the book of philanthropy as a good. Liz, the wife of the protagonist, Luther, pins a clipping of a San Francisco Chronicle article about Bay Area philanthropy to the refrigerator, with a picture of her sister and two daughters on the porch of their hilltop Victorian. Luther asks Liz if her life with “no black-tie fund-raisers. No big house. No girls in velvet dresses,” was disappointing. “Oh Luther,” Liz answers. “I don’t envy Trish because her life is fancy. I envy her because she’s so important.”

A Honda minivan and a book tour

The kind of philanthropy portrayed in “The Testing of Luther Albright” resembles the sort practiced by her mother, Holiday Tuttle. In California, Ms. Tuttle had worked on fund-raisers for a museum and a private school as well as volunteering to save the trees. In Florida, she threw herself into the community with gusto.

In 1991, in the celebratory mood after the Persian Gulf war, she was an organizer of the Palm Beach Fourth of July parade. “We want to salute our veterans and show them the respect and gratitude that they deserve,” Ms. Tuttle told the Palm Beach Daily News, four years after the bankruptcy filing. She worked on a toy drive for the children of farmworkers and on fund-raisers for breast cancer.

Ms. Scott and Mr. Bezos began to make their own forays into the charitable world. In 2004, the couple joined the board of the Bezos Family Foundation, a charitable vehicle of Mr. Bezos’ parents, who became extraordinarily rich in their own right from their early infusions of capital into the fledgling Amazon.com. Since Mr. Bezos and Ms. Scott joined the board, tax records show, the foundation has given away more than $300 million.

In 2011, Mr. Bezos and Ms. Scott donated $15 million to Princeton for a center to study the brain. The following year they gave $2.5 million in support of a same-sex marriage referendum. “Their gift was incredibly consequential,” said Zach Silk, campaign manager of Washington United for Marriage, completely changing the scale of what had been a “pretty scrappy” but somewhat underfunded effort.

When Ms. Scott’s second novel, “Traps,” was published in 2013, the extremely private Ms. Scott cracked the door to her life open to the public again to promote her book, sitting for a profile complete with photos by Vogue magazine, meeting the reporter at a Thai restaurant in Bellevue, Wash. Ms. Scott took pains on her publicity tour to demonstrate how normal she was, how she drove a regular Honda minivan when she took their by-then four children to school.

One of the main characters in “Traps” is a famous actress named Jessica, who worries about security and employs a bodyguard. At one point, as she approaches the bodyguard’s car, Jessica thinks, “She will not try to influence this woman’s opinion. She will not work to project what she wants others to see (Kind! Down-to-earth! Humble! Normal!).”

The year after the book appeared, in April 2014, Ms. Scott launched her own organization, Bystander Revolution, which was a “website offering practical, crowdsourced advice about simple things individuals can do to defuse bullying and help shift the culture.”

Ms. Scott made cold calls and assembled an informal group of advisers. Dorothy L. Espelage, a psychologist specializing in bullying prevention, recalled in an interview how she was sitting in a parking lot at the University of Illinois, where she worked at the time, when her phone rang. It was Ms. Scott. “She called me and was like, ‘Oh my god, my kid’s being bullied, and as a parent I’ve found there’s not a lot of resources,’” said Dr. Espelage, now a professor at the University of North Carolina.

Dr. Espelage said she advised Ms. Scott to draw on real stories and engage celebrities as ambassadors. A small team led by a recent Princeton graduate helped produce video testimonials by a range of public figures, including Monica Lewinsky and the actor Jared Leto.

But after a big launch, the site seemed to fizzle. The private Ms. Scott was founder and executive director but appeared to prefer not to serve as the face of the organization, instead letting the stars take center stage.

Yet the more she avoided the spotlight, the more it seemed to find her. In 2018, Forbes magazine named Mr. Bezos the richest man in the world, bringing a new level of attention and scrutiny on him, on his company and, by extension, on her.

Until the safe is empty

The couple traveled to Florida in May 2018 for a glitzy celebration of Ms. Scott’s parents’ 55th wedding anniversary. Ms. Tuttle has been actively involved in a women’s group associated with St. Edward’s Roman Catholic Church, where the Kennedy family was once known to attend Mass, and Mr. Tuttle has served on the board of directors for the couple’s condominium association in a gated community with a golf course in West Palm Beach.

It is not clear how the Tuttles revived their fortunes so completely. In addition to Ms. Tuttle’s work at boutiques, public records indicate that before the subprime meltdown, Mr. Tuttle was licensed in Florida as a mortgage broker, a real estate broker and assistant appraiser and registered half a dozen shell companies with names like FAMCO Group and REALCO Group.

Calls to Mr. and Ms. Tuttle for comment were not returned.

The luminaries in attendance at the anniversary party, aside from Mr. Bezos and Ms. Scott, were of a decidedly right-wing bent. According to the Palm Beach Daily News, the radio host Rush Limbaugh, the Fox News personality Laura Ingraham and Ann Coulter were all in attendance, as was Roger Ailes’s widow, Liz. Records show that Mr. Tuttle made a small contribution — $25 — to the Ron DeSantis campaign for Florida governor that year, while Mr. and Ms. Tuttle had each previously contributed $500 to the Republican National Committee.

That same year, in September, Mr. Bezos and Ms. Scott pledged $2 billion to open Montessori-inspired preschools and support homeless families. It was their biggest commitment to charity yet and likely among their last as a couple. In January 2019, Ms. Scott and Mr. Bezos jointly announced on his Twitter account that they were divorcing.

Her first big statement as a newly single woman came less than five months later on the website of the Giving Pledge, started by Bill Gates, Melinda French Gates and Warren Buffett as a place where billionaires promised to give away at least half their wealth. Ms. Scott went further, promising to “keep at it until the safe is empty.”

The Giving Pledge is a public promise and little more. It has no donation schedules, no reporting requirements and no enforcement mechanisms. Still, it was a significant statement.

Nonprofits soon began receiving calls and emails about enormous grants from an anonymous donor, often the biggest donation in the group’s history or the equivalent of a full year’s budget. Some of those approaches were from staff at the influential nonprofit consultancy Bridgespan, others from representatives at Lost Horse. The chosen charities were told they could not announce the gifts until the donor did.

On July 28, 2020, Ms. Scott tweeted a link to a post on the website Medium, where she unveiled the scale of her ambition as a philanthropist. In the tweet, she added in a parenthetical: “(Note my Medium account is under my new last name — changed back to middle name I grew up with, after my grandfather Scott.)”

On Medium, she was writing in the language of equity and social justice, guiding philosophies for her giving. “Personal wealth is the product of collective effort,” she wrote, “and of social structures which present opportunities to some people, and obstacles to countless others.”

She gave overwhelmingly to groups led by women, people of color, members of the L.G.B.T.Q. community or all three. The total amount of grants she was announcing came to $1.7 billion.

She gave big. She gave fast. She gave with few strings attached. And unlike with Bystander Revolution, she was front and center.

“My own reflection after recent events revealed a dividend of privilege I’d been overlooking: the attention I can call to organizations and leaders driving change,” she said, in her first public catalog of her giving. She put herself out there but not at the public events that, by her own admission, made her uncomfortable, yet using the skill she’d been honing since she was eating Oreos and reading botany books: her writing.

Her gifts were the talk of charitable circles. It did not escape notice at the Ford Foundation, for instance, that more than half the groups she had given to were among its grantees.

Commentary was overwhelmingly positive, but philanthropy experts raised significant questions. Ms. Scott did not have a foundation that would have to file detailed tax returns. Instead, she gave through the lightly regulated vehicles known as donor-advised funds, which meant she could make massive, tax-deductible donations with no transparency requirements.

If there were causes she supported but did not want the world to know about, she could simply choose not to include them in the Medium post.

“Her preferences are shaping the face of American civil society because of the size of the funding she’s providing,” said Rob Reich, co-director of the Center on Philanthropy and Civil Society at Stanford University. “That power deserves civic scrutiny and attention.”

Those concerns were temporarily overshadowed when, less than five months later, on Dec. 15, 2020, Ms. Scott announced another, even bigger round of giving, $4.2 billion to 384 organizations, including hundreds of Easterseals, United Way, Y.W.C.A. and Y.M.C.A. chapters, groups that were doing a lot of good on the front lines during the pandemic but not the kind of innovation-focused giving that the Silicon Valley set prioritizes. Some were groups that her mother might have gone to a luncheon for in Palm Beach, or her grandmother in El Paso.

Three days later, on Dec. 18, 2020, the change of her last name to Scott was legal and official, according to court records from Bellevue, Wash. In a deeper sense, her public identity had also changed. She was no longer seen publicly as Jeff Bezos’ ex-wife first. She was MacKenzie Scott, the novelist upending philanthropy. She had become important with no black-tie fund-raisers and no velvet dresses.

A chemistry teacher signs the Giving Pledge

Shortly before the pandemic hit, the chemistry teacher Dan Jewett took on a delicate, sometimes unpopular task. He was asked to run a fund-raising campaign at Seattle’s prestigious Lakeside School, where he taught and which seeks donations from the moderately paid faculty and staff members to a school with assets of $325 million and multiple billionaires in its tightknit community. Bill Gates is among its alumni, and Jeff Bezos and MacKenzie Scott are among the parents.

Mr. Jewett took on the assignment and got inventive, suggesting that faculty donations go toward students on financial aid, rather than to the school itself, a former Lakeside colleague recalled. He showed ease operating in a world of giving that he would soon come to know far more significantly, and that year’s annual fund became among the most successful, said the former colleague, who asked not to be named out of concern it could affect employment.

Mr. Jewett lived in a modest house and had separated from his wife in 2018. Like Ms. Scott, he got divorced in 2019. It came as a huge surprise even to many at the school when the news emerged in March 2021 that the billionaire philanthropist and the chemistry teacher had wed a few weeks earlier. He was informing friends, he told them at the time, because the news was about to come out in the tabloids.

Before that could happen, the couple announced their wedding in a backhanded way. Mr. Jewett posted his own letter on Ms. Scott’s Giving Pledge page. And Ms. Scott changed her author bio on the Amazon website to read: “She lives in Seattle with her four children and her husband, Dan.” Mr. Jewett’s Twitter page abruptly vanished, leaving behind ghostly traces of an account where colleagues had bantered with him about science.

Mr. Jewett was the kind of teacher students appreciated, jovial in manner and serious about his subject. At an alumni event in the Bay Area in late January 2020, shortly before the pandemic sent America into lockdown, Mr. Jewett stole the show with his “humor and enthusiasm,” as the alumni magazine put it, and improbably won the crowd over with a joke about “trigonal planar molecules.”

He was known among fellow teachers for giving high-fives to all the faculty members on Friday afternoons. Mr. Jewett had been scheduled to teach this academic year, according to a former colleague, but at the end of the 2021 school year, just a few months after the marriage was announced, he left Lakeside.

A gift from Lost Horse

Over the past year, Ms. Scott has announced grants totaling $6.6 billion. For comparison, the Gates Foundation said it paid out $5.8 billion in grants in 2020, the most recent year for which complete data is available.

By most measures the world’s largest charitable foundation, Gates made those grants with a staff of over 1,700 employees. It is unclear exactly how big Ms. Scott’s own staff is, but it is believed to be a small fraction of the Gates team.

The media company Puck has reported the names of a handful of Lost Horse associates, including that of her adviser Hillary Chen, who previously worked at both the White House Office of Science and Technology and for Ms. French Gates’s group, Pivotal Ventures. Ms. Scott is friendly with Ms. French Gates, people in philanthropic circles in Seattle say, and the two billionaires have worked together on programs like the Equality Can’t Wait Challenge, a $40 million gender-equality initiative.

Last June, Ms. Scott announced another round of giving, $2.7 billion this time. She had pledged to give “until the safe is empty” but her remaining Amazon shares were worth more than at the time of the divorce, the result of a soaring market that fueled further debate over billionaires and income inequality.

That was when she published a new letter this past December, the one where she opened up about her struggles during college, showed more of herself, but with the headline, “No Dollar Signs This Time,” which meant both that the symbol “$” wasn’t used, but also that she did not say how many billions had gone out the door since June. She was removing the spectacle from the proceedings.

Critics complained that she had retreated into less transparency rather than share more information, as nonprofit governance experts had called for. But something unusual happened. Ms. Scott, who follows no one on Twitter, and who has given no interviews about her philanthropy, responded to the discussion with another note including “a paragraph I wish I hadn’t cut from the essay,” about releasing more data in the year to come. She had meant to say that her team was building a website, the plans for which included a “searchable database of gifts.”

She has built a philanthropic operation that is notable not just for the monumental size and speed of its gifts but also for its seemingly impenetrable secrecy. Unlike Laurene Powell Jobs’s Emerson Collective or Ms. French Gates’s Pivotal Ventures, Ms. Scott avoided establishing a website or advertising any contact information.

For some nonprofits, curiosity has curdled into fear, as leaders fret that when their peers receive grants from Ms. Scott and they are passed over, it could imply that they are mismanaged or ineffective. Her opaque methodology is the subject of regular hushed conversations in the nonprofit field. No one wants to offend her, but the choices can appear capricious. Why one chapter of the Y.M.C.A. and not another?

On paper, Lost Horse’s headquarters are a law firm office in a downtown Seattle skyscraper and a tax firm in Los Angeles that handles family offices for high-net-worth individuals.

Public records also show that Lost Horse has an office of its own in a brand-new eco-friendly building in Seattle. In keeping with the absolute secrecy surrounding Lost Horse’s operations, there is no nameplate in the lobby and the slim rectangular window on the Lost Horse floor is papered over. On a recent morning no one answered the door or the phone.

A man who appeared to be a security guard at an address linked to another shell company in an affluent corner of Seattle said, “They’re not available at the moment.”

Shortly after a reporter appeared at those addresses seeking comment last month, Ms. Scott published her latest missive on Medium, announcing another $3.86 billion in gifts, and returning to her practice of noting the total dollar value of her gifts.

In it she seemed to address the contradictory urges of preserving privacy while commanding attention for the causes she supported. Her approach to press inquiries, she wrote, involved “respecting the autonomy and role of journalists by doing nothing to try to influence or control what they report.”

“We are all human,” she wrote in the post. “And we all have enormous energy to devote to helping and protecting those we love.”

Karen Weise contributed reporting. Kitty Bennett contributed research.