Borrow Against Your Company Stock or Sell It? The Fork Before a Down Payment or April Tax Bill

Borrowing against company stock can cover a short gap without a sale, but it is a callable loan secured by one stock. FINRA says a typical securities-backed line lends 50 to 95 percent of account value, depending on what the account holds (2024). For recently vested RSUs, the gain on a sale is measured from the vest-date value.

The fork, stated plainly

You need a large amount of cash inside the next 12 months. Maybe it is the down payment on a house in Carmel Valley or North Park. Maybe it is the April bill from a year of RSU vests that were under-withheld. Most of your liquid net worth is shares of the company you work for.

Two branches. First, sell enough shares to cover the need and pay whatever tax the sale creates. Second, keep the shares and borrow against them through a securities-based line of credit (SBLOC), then pay the line back later from something else.

Both work. The question is which risk you would rather carry for the next year: a tax bill you can see today, or a loan whose terms depend on one stock price you do not control.

Why the gain on a sale starts at the vest-date value

When RSUs vest, the value of the shares is taxed as wages right then, sold or not. Under 26 CFR 1.61-2(d)(2)(i), your basis in shares received as pay is the amount you paid for them plus the amount included in your gross income. For RSUs, that basis equals the value of the shares on the vest date. So if you sell shares that vested in March and the price has barely moved, the sale creates very little additional gain. The big tax already happened at vest.

The tax on a sale is only on the movement since vest. Held a year or less, that gain is short-term and taxed at ordinary rates. Held longer, it is long-term. California has no lower capital gains rate and taxes all capital gains as ordinary income, so the holding period does not change your state rate (California Franchise Tax Board, updated January 2026). Keep in mind the 3.8 percent net investment income tax can also apply once modified adjusted gross income is above $200,000 single or $250,000 married filing jointly (IRS Topic 559, reviewed 2026).

Where selling does get expensive is older shares with a large gain, or ESPP shares sold before the holding periods are met. Those periods run more than 2 years from the option grant and more than 1 year from the date the shares were transferred to you (26 U.S.C. 423(a)(1)), and selling sooner means part of the gain is taxed as ordinary income (IRS Publication 525, 2025). The mechanics are in how an ESPP actually works. That is a real cost. It is just not every share you own.

Why the April bill shows up in the first place

Run the arithmetic on a common San Diego case. Your employer withholds federal tax on RSU vests as supplemental wages, and the flat rate is 22 percent, rising to 37 percent only on supplemental wages above $1 million for the year (IRS Publication 15, 2026). But for 2026, a single filer’s income above $256,225 is in the 35 percent bracket, and above $640,600 it is 37 percent (IRS news release IR-2025-103, October 2025). A single filer deep in the 35 percent bracket with $100,000 of vests had $22,000 withheld against roughly $35,000 of federal tax on those dollars. That is a $13,000 federal gap (illustration only, before California, and your real number depends on the whole return).

That gap is usually what people are trying to solve when they ask about borrowing. The ways to cover it, and why the IRS does not treat them the same, are in two ways to cover an RSU tax shortfall.

What borrowing actually commits you to

An SBLOC is not a mortgage and not a margin account, though it rhymes with both. A few mechanics decide whether it fits.

First, it is a demand loan. FINRA puts it directly: “Keep in mind that SBLOCs are classified as demand loans, which means lenders may call the loan at any time” (FINRA, “Securities-Backed Lines of Credit Explained,” January 2024).

Second, the collateral is marked to market. If the shares fall, the lender can issue a maintenance call. If you cannot meet it, the firm can sell your securities, and FINRA notes lenders often can do that without notice. A forced sale creates the capital gains tax you were trying to avoid, at a lower price, on a date you did not pick.

Third, what you can borrow depends on what you hold. FINRA ties its 50 to 95 percent range to how much the account holds overall and what kinds of assets are in it, and it specifically warns that a portfolio concentrated in one stock or sector can drop fast enough from a single event to trigger a maintenance call. If most of the account is your employer’s stock, ask the lender how much it will advance against those shares before you plan around a number.

Fourth, the money cannot buy securities. SBLOCs are non-purpose loans. When a bank or other lender that is not a broker or dealer extends credit to buy or carry margin stock, the Federal Reserve’s Regulation U applies, and 12 CFR 221.7(a) caps the loan value of margin stock at 50 percent of its current market value. A margin account at a brokerage firm is covered by a separate rule, Regulation T (12 CFR Part 220). Both are different products with different rules (eCFR, current as of September 2026).

Fifth, the interest is usually not deductible for these uses. Interest on borrowing for personal purposes is generally nondeductible personal interest, and the mortgage interest deduction applies to a loan secured by your main or second home (IRS Topic 505, reviewed 2026). A line secured by your brokerage account is not that. Investment interest is a separate category limited to net investment income. Confirm how your own situation is treated with your CPA before counting on any deduction.

Two more checks that are easy to miss. Confirm whether your company’s insider trading policy restricts pledging company shares. And if the cash is for a down payment, confirm with your mortgage lender how they treat borrowed funds, because the line is a debt they may count.

Sources: FINRA, “Securities-Backed Lines of Credit Explained,” 2024. IRS Topic 559 (NIIT) and Topic 505 (interest expense), both reviewed 2026. Tax treatment varies by return. Confirm with your CPA.

When borrowing is the better branch

Here is where you would be right to borrow. When people ask me whether there is a portfolio size where an SBLOC beats selling, my answer is that size is not really the question. The variables are. Why do you need the money. What is the rate. What is the payback schedule. Is this a one-time thing. And are there other options that would lead to a better outcome.

So the case for borrowing gets strong when the need is one-time, the payback has a known source and date (a vest next quarter, a bonus in March, the sale of a current home), the amount borrowed is small relative to the account, and the account holds more than company stock. It gets weak when the payback plan is “the stock will go up,” when the shares are most of the collateral, or when a drop of a third in your employer’s price would put you in a call you could not meet from cash.

The price of admission for evaluating this honestly is short: a current statement of every holding, your vest schedule for the next 12 months, the amount and date of the need, and where the payback is coming from. Without those four, nobody can tell you which branch is cheaper. For a look at whether to keep concentrated shares at all, see when to hold or sell a concentrated RSU position after vesting.

A question to ask whoever suggests the loan

FINRA notes that an investment professional may be paid a share of the fees your SBLOC generates, and also benefits when you do not sell assets (2024). That does not make a line of credit a bad idea. It does mean it is fair to ask any advisor who suggests one, including us, how they or their firm are compensated in connection with the lending, before you sign. A straight answer to that is part of the decision.

If your payback depends on future vests, put the vest calendar, the April bill and the closing date side by side before you pick a branch, the way the San Diego HENRY strategy lays out equity comp, tax and debt decisions together.

FAQ

Is borrowing against my stock a way to avoid capital gains tax?

It defers the sale, not the tax. If you later sell to repay the line, the gain is taxed then. If the stock falls and the lender sells to meet a maintenance call, the gain is taxed on their timing. For shares that vested recently, the gain you would be avoiding may be small to begin with, because the vest value was already taxed as wages and became your basis.

Can I use an SBLOC to buy more shares or other stocks?

No. FINRA describes SBLOCs as non-purpose loans, meaning the proceeds cannot be used to purchase or trade securities. Credit to buy or carry margin stock is a different arrangement. From a bank or other lender that is not a broker or dealer, it falls under Federal Reserve Regulation U, which limits the loan value of margin stock to 50 percent of its current market value (12 CFR 221.7(a)). A margin account at a brokerage firm falls under Regulation T (12 CFR Part 220).

How much can I borrow against company stock?

FINRA says a typical agreement allows 50 to 95 percent of the account's value, depending on overall holdings and the types of assets (2024). FINRA also warns that a portfolio concentrated in one stock can fall fast enough to trigger a maintenance call. Because the amount depends on what you hold, ask the lender for the number in writing before you plan around it.

Is the interest tax-deductible if I use it for a house?

Generally no. The mortgage interest deduction applies to debt secured by your main or second home, and a line secured by a brokerage account is not that (IRS Topic 505). Interest used for personal purposes is usually nondeductible personal interest. Confirm your specific situation with your CPA.

Is it better to sell now or wait for the next vest?

It depends on timing and the size of the gap. If the need is months away and the next vest covers it, waiting may avoid both a sale of older shares and a loan. If the need is fixed, like a closing date or April 15, list the vests that land before that date and what each one nets after withholding. The shortfall left over is the amount you are actually deciding to sell or borrow.

Which is it for you, a down payment or an April bill, and do you know where the payback comes from? If that last part is fuzzy, it is usually a short conversation with a statement and a vest schedule in front of us. Book a complimentary review and we can map both branches before you commit to either.

Hope that helps.