Reserve Primary Fund: Broke the Buck, Money Market Run

Money market funds are supposed to be the financial world’s blandest snack: no spice, no surprises, and definitely no
“why is this crunchy?” moments. You park cash, earn a little yield, and move on with your life.
That’s the deal.

In September 2008, the Reserve Primary Fund turned that deal into a jump-scare. It “broke the buck,” meaning its
share price fell below the iconic $1.00. And what looked like a small crack in one fund’s armor became a stampede
across the cash-management ecosystema modern money market run that threatened payrolls, corporate funding, and the
short-term credit markets that keep the real economy awake and caffeinated.

The Reserve Primary Fund Wasn’t Just Any Fund

The Reserve Primary Fund sat inside the broader money market mutual fund universefunds designed to provide
liquidity and preserve principal by investing in short-term, high-quality debt. For decades, investors treated many
money market funds like “cash with a little extra,” assuming a stable $1 net asset value (NAV) was basically a law
of nature.

The Reserve family had history and brand recognition. But in a crisis, history is comforting only until it isn’t.
Once confidence cracks, the math starts to matter more than the marketing.

What “Broke the Buck” Really Means (And Why It’s a Big Deal)

“Breaking the buck” happens when a money market fund’s NAV drops below $1.00. That’s not supposed to occur often,
because these funds are managed to maintain stability using strict limits on credit quality, maturity, and
diversification. Many funds also use methods that keep the NAV at $1.00 under normal conditions (like amortized
cost accounting and “penny rounding”), which works greatuntil it suddenly doesn’t.

Here’s the psychological trap: once investors believe the $1.00 NAV is guaranteed, a mere possibility of
loss changes behavior. If you think the fund might be worth $0.99 tomorrow, you have a powerful incentive to redeem
todayespecially because early redeemers often get paid out at $1.00 while the remaining shareholders eat the
losses and illiquidity. That’s the classic run dynamic: not “I’m sure there’s trouble,” but “I can’t afford to be
last.”

The Spark: Lehman, a Write-Down, and a Confidence Collapse

On September 15, 2008, Lehman Brothers filed for bankruptcy. The Reserve Primary Fund held Lehman-issued
securitiesreported as roughly $785 millionand the fund quickly became illiquid as redemption requests surged.
The next day, Reserve Primary disclosed that it had broken the buck, with the NAV falling below $1.00widely
reported as about $0.97 at the time. In plain English: the fund that people used like a cash equivalent was no
longer cash-equivalent-ing. Not even a little. Not even for one terrifying news cycle.

What’s striking is that the Reserve Primary Fund’s Lehman exposure was a relatively small slice of assets in
percentage terms in many retellings. But crises don’t require giant losses to trigger giant reactions. They require
uncertainty, speed, and the sudden realization that “liquid” assets can become “liquid-ish” right when everyone
wants the exit at once.

In the days immediately following Lehman’s failure, investors slammed money market funds with redemption requests,
especially prime money market fundsthose that hold not only government debt but also private
short-term instruments like commercial paper and bank obligations. Outflows reached hundreds of billions in a very
short window. When cash investors run, they don’t jog politelythey teleport.

How a Money Market Run Spreads (Fast)

A money market run is a chain reaction. It starts with one fund or one category of holdings that investors worry
might be impaired. Then investors begin redeeming from other funds that look similar. Even if those other funds
don’t hold the same risky paper, investors often don’t have timeor patiencefor nuance.

Step 1: Redemptions Force Asset Sales

Funds meet redemptions by using cash, selling their most liquid holdings, or letting maturing securities roll off.
In normal markets, that’s fine. In stressed markets, selling can mean taking lossesor discovering that certain
instruments simply don’t have buyers at anything close to par.

Step 2: Liquidity Becomes a Scarce Resource

When many investors redeem at once, funds may sell the easiest-to-sell assets first, leaving remaining shareholders
with a less liquid portfolio. That can intensify incentives to redeem early, making the run self-reinforcing.

Step 3: Short-Term Funding Markets Freeze

Money market funds are major buyers of commercial paper and other short-term funding instruments. When funds pull
back from buyingor are forced to sellissuers face a funding crunch. That matters because commercial paper helps
finance routine corporate operations like inventory and payroll. Suddenly, “a fund problem” becomes “an economy
problem.”

Step 4: The Safe-Haven Stampede

Investors often flee prime funds for government money market funds or Treasury instruments. In 2008, a significant
portion of the cash that left prime funds moved into government and Treasury fundssame investors, different level
of perceived safety. The money didn’t vanish; it just relocated to the financial equivalent of a bunker.

The Emergency Response: Backstops, Facilities, and a Confidence Repair Job

Once policymakers saw the run spreading and short-term funding markets straining, they moved quickly to provide
confidence and liquiditytwo things markets always want, especially when they’re least available.

The Treasury’s Temporary Guarantee Program

The U.S. Treasury announced a temporary guarantee program for money market funds, designed to reassure investors
and reduce incentives to run. The program generally provided coverage for participating funds based on
shareholders’ balances as of the close of business on September 19, 2008. The guarantee would be triggered if a
participating fund’s NAV fell below $0.995 (a common definition of “breaking the buck” in that framework).

The messaging here wasn’t subtle: “We’re putting a net under the tightrope.” And when you’re trying to stop a run,
confidence effects can matter as much as cash flows.

The Federal Reserve’s Liquidity Facilities

The Federal Reserve introduced and expanded facilities aimed at restoring liquidity in short-term markets and
helping money market funds meet redemptions without dumping assets into a fire sale.

• AMLF (Asset-Backed Commercial Paper Money Market Mutual Fund Liquidity Facility): provided
  funding to banks to purchase high-quality ABCP from money market funds, helping funds raise cash while supporting
  ABCP market functioning.
• MMIFF (Money Market Investor Funding Facility): intended to support liquidity by facilitating
  purchases of certain money market instruments, aiming to bolster investor willingness to hold longer-term money
  market assets.
• CPFF (Commercial Paper Funding Facility): created to backstop commercial paper issuance and
  reduce the pressure on short-term funding marketscritical when private buyers step away.

These tools all targeted the same underlying issue: money market funds promise daily liquidity, but many of their
assets become harder to sell under stress. Policymakers essentially tried to widen the exit doors and keep the
building from catching fireat the same time.

What Happened to Reserve Primary Fund After the Break

Following the breaking-the-buck announcement and the freeze in redemptions, Reserve Primary’s assets moved through
a liquidation process overseen through regulatory and court actions. Over time, assets were distributed back to
investors as the portfolio matured and positions were unwound. While the immediate panic was about liquidity, the
longer story involved valuation, recoveries, and the slow, procedural work of returning cash in a stressed
environment.

The headline lesson: even when eventual investor losses are smaller than feared, the timing of access to
cash can be the real shock. For people and institutions using money market funds as operational cash, “eventually”
is not a satisfying adverb.

The Regulatory Aftermath: How the Rulebook Changed

The 2008 run didn’t just leave scars; it rewrote standards. Regulators focused on reducing run risk, improving
liquidity buffers, and increasing transparencywhile trying to preserve the usefulness of money market funds as cash
management tools.

2010 Reforms: More Liquidity, More Testing, More Transparency

After the crisis, the SEC amended Rule 2a-7 and related requirements to strengthen portfolio liquidity standards,
risk management, and disclosure. Among the major shifts were explicit minimum levels for daily and weekly liquid
assets for many funds, plus expectations around stress testing and oversight. The idea was straightforward: if runs
are fueled by fear of illiquidity, give funds more liquidity to begin withand require them to prove (in modeling)
that they can handle stressful redemption scenarios.

2014 Reforms (Implemented Later): Floating NAVs and the “Fees and Gates” Era

The SEC took another big swing in 2014. Institutional prime money market funds were required to move away from a
stable $1.00 NAV toward a floating NAV, reflecting market-based pricing. In addition, rules allowed for liquidity
fees and temporary redemption gates under certain conditions tied to liquidity thresholdsan attempt to make the
cost of liquidity more explicit and slow down run dynamics.

These changes reshaped the industry, including a notable migration from prime funds toward government funds in many
cash-management programs. In practice, rules can change behavior in ways that aren’t purely academic: if investors
expect fees or gates during stress, they may run earlier. That tension has been central to the ongoing
debate about money market structure.

2023 Reforms: Higher Liquidity Minimums, Gates Removed, Liquidity Fees Reworked

More recently, the SEC adopted additional reforms in 2023 after stress episodes that highlighted lingering
vulnerabilities. The amendments increased minimum daily and weekly liquid asset requirements (to 25% and 50%,
respectively) for many funds, removed the rule provisions that permitted redemption gates, and introduced a revised
liquidity fee framework intended to better allocate liquidity costs to redeeming investorsespecially in high
outflow days.

In other words: policymakers kept the focus on the same core problemliquidity mismatch and first-mover
incentiveswhile adjusting the toolkit based on how markets actually behaved, not how we hoped they would.

Why the 2008 Money Market Run Still Matters Today

The Reserve Primary Fund episode is not just financial crisis trivia. It’s a case study in how modern finance can
be vulnerable even in places designed to be boring.

1) “Cash-Like” Is Not “Cash”

Money market funds are investment products, not insured bank deposits. They are built to be stable, but stability
depends on asset quality, liquidity, and market functioning. If your plan assumes “same-day access no matter what,”
you’re implicitly assuming a crisis never happens. That’s a bold strategy, especially for a species that invented
both hurricanes and conference calls.

2) Prime vs. Government Funds Isn’t Just a Label

Prime funds typically reach for a bit more yield by holding private short-term credit. That can be perfectly
reasonable in calm markets. But during systemic stress, investors tend to prefer government-backed liquidity. The
2008 experience showed how quickly “yield pickup” can turn into “yield who?”

3) Liquidity Is a FeatureUntil Everyone Uses It at Once

Daily liquidity is attractive, but it also creates the possibility of runs. The system becomes fragile when many
participants rely on the same “always available” cash tool and then demand it simultaneously.

4) Backstops Can Stop RunsBut They Raise Big Questions

Government support can calm markets. But it also raises policy questions about moral hazard: if investors assume
money market funds will be backstopped in severe stress, they may treat them as safer than they truly are, which
can encourage risk-taking and amplify the stakes of future crises.

Practical Takeaways for Investors and Cash Managers

If you’re managing cashpersonally, for a business, or for an institutionhere are practical ways to apply the
Reserve Primary lesson without turning your budget spreadsheet into a horror novel.

Build a “Cash Ladder,” Not a “Cash Cliff”

Don’t rely on one vehicle for all liquidity needs. Consider segmenting:
operating cash (immediate), near-term reserves (weeks to months), and strategic reserves (longer-term). Different
tools serve different time horizons.

Know What Your Fund Owns and What Rules It Follows

Read the fund’s category (government, prime, tax-exempt), investor base (retail vs. institutional), and liquidity
disclosures. It’s not about memorizing CUSIPs; it’s about understanding whether your “cash” depends on the health
of private short-term credit markets.

Stress-Test Your Own Assumptions

Ask: “What happens if I can’t access this cash for a week?” If that answer involves missed payroll, missed margin,
or angry clients, you may need a more conservative liquidity buffer or diversified access points.

Don’t Ignore Behavior Risk

The risk isn’t only what the fund holds; it’s how other investors react. In a run, you are not trading against a
spreadsheetyou are trading against human fear, institutional policy triggers, and the fact that everyone suddenly
remembers where the “redeem” button is.

500-Word Experience Add-On: What “Broke the Buck” Felt Like in the Real World

I don’t have personal memories, but the Reserve Primary Fund episode has been described so consistently by market
participants over the years that you can piece together what the experience was like on the ground. Think of this
as a composite of common stories from cash managers, advisors, and fund professionalsan “it was like this” add-on
rooted in how the mechanics of the run actually worked.

For a corporate treasurer, the week felt less like “portfolio management” and more like “emergency
logistics.” The fund wasn’t a risky bet; it was the place to store payroll cash and vendor payments. Then headlines
hit: NAV below $1, redemptions halted, markets frozen. The treasurer’s world shrank to three questions:
“How much cash do we have right now?” “Where else can we move it today?” and “How do I explain this to leadership
without sounding like I stored the company’s money in a vending machine?”

For financial advisors, it was a phone marathon. Clients who had never asked about a money market
fund’s holdings were suddenly demanding to know whether their cash was “safe.” Some calls weren’t even about
investment returns; they were about access. The emotional center of the crisis wasn’t “I might lose a few
cents,” it was “I might not be able to use my money when I need it.” Advisors had to translate plumbingcommercial
paper, liquidity, sponsor supportinto plain language while the news ticker kept screaming.

For fund managers, it was triage under fluorescent lighting. The job is normally about risk limits,
maturity schedules, and incremental yield. During the run, the job became: raise liquidity without blowing up the
portfolio, communicate without triggering more panic, and make decisions that are fair to both redeeming and
remaining shareholders. It’s an ugly paradox: the more transparent you are about stress, the more you might
accelerate stress. But the less transparent you are, the more investors assume the worst. Either way, you’re
managing finance and psychology at the same time.

For everyday investors, the “experience” was confusion. Many people didn’t know money market funds
could break the buck at all. The $1.00 share price looked like a promise. When that promise wobbled, people
realized they had been using a market product as if it were a bank account. That realizationmore than the pennies
at riskwas what changed behavior for years afterward.

The lasting takeaway from these experiences is simple: in a crisis, liquidity is not a convenience; it’s a
lifeline. Reserve Primary Fund didn’t just lose valueit revealed how quickly confidence, structure, and
short-term credit can interact. And once you’ve seen cash behave like a crowd at a single exit, you never look at a
“boring” fund the same way again.