Rambus (RMBS) Q3 2026 earnings review
Rambus chip sales speed up, but its inventory nearly doubles
Rambus, which makes memory interface chips and licenses technology for data centers, grew sales while keeping research costs flat. Total revenue rose 22% from a year ago, and profit per share excluding one-offs climbed 35% as royalties beat the company's plan. Chief executive Luc Seraphin forecast an even stronger fourth quarter, with the outlook pointing to 34% yearly growth in product sales by our math.
| Revenue | $218.3M +22.3% from a year ago |
|---|---|
| Product revenue | $114.3M +22.5% from a year ago |
| Profit per share, excluding one-offs | $0.84 +35.5% from a year ago |
| Q4 revenue outlook | $227–233M middle of the range: 20.9% growth |
⚖️ Verdict: 🟢 Bullish
The story got better because fourth-quarter product growth is speeding up and management put $135 million of idle cash into share buybacks. Operating margins also expanded again after shrinking in the first half of the year. One caution: beating the third-quarter royalty plan says the plan was cautious, not that licensing swings have ended, and unsold inventory has nearly doubled since December while product gross margin slipped.
The question now is whether the fourth-quarter product jump comes from newer companion chips taking a bigger share of each server, or simply a wider server buying cycle that could unwind if customers over-ordered. If companion chips drive it, product gross margins and share per server rise; if it is just a server cycle, the $87 million inventory pile is a risk. The conference call update on companion-chip share will tell.
🐂 Bull Case
Product Sales Accelerate Into Year-End
Rambus makes memory interface chips that help data center servers move information faster between processors and memory. Chief executive Luc Seraphin said "Rambus delivered record quarterly revenue and earnings that exceeded our guidance, with strong customer demand driving record product revenue and record cash from operations". Product sales rose 22.5% from a year ago to $114.3 million, even against a year-ago quarter that grew 41%.
The fourth-quarter outlook shows the chip business speeding up rather than slowing on tough comparisons. The company plans for $127 million to $133 million in fourth-quarter product revenue. At the middle of the range, by our math, product sales grow 13.7% from this quarter and 34.3% from a year ago. That is the fastest yearly growth rate in four quarters, showing that server demand and chip adoption are overcoming assembly bottlenecks.
What to watch: fourth-quarter product revenue against the $130 million middle of the range. Landing above that mark would prove that factory packaging limits are not capping shippable server demand.
Management Put $135 Million Into Share Buybacks
For the first half of the year, the chip and licensing group let cash pile up on its balance sheet, spending just $3 million on buybacks while cash and securities reached $824.9 million. In the third quarter, Rambus spent $135.4 million "paid for repurchases of common stock". That outlay exceeded the quarter's free cash flow and trimmed total cash and marketable securities to $776.9 million.
The buyback immediately reduced the diluted share count from 110.0 million in the second quarter to 108.8 million, beating the 110 million share assumption in the company's prior plan. What to watch: fourth-quarter diluted share count against the 109 million outlook assumption. A further drop would show the buyback continued beyond the third quarter.
Flat Research Spending Lifted the Operating Margin
Over the prior two quarters, reported operating margin fell from a year earlier because restructuring charges and higher overhead outpaced sales. This quarter reversed that compression. Reported operating margin rose 2.9 percentage points from a year ago to 38.3%, while operating margin excluding one-offs climbed 2.5 percentage points to 46.8%. Research and development, the cost of designing new chips, stayed flat at $49.4 million, dropping 5.1 percentage points of revenue.
The fourth-quarter outlook keeps operating margin excluding one-offs at 47.0% at the middle of the range by our math, confirming the rebound holds. What to watch: sales, general and administrative expense, which still rose 0.9 percentage points of revenue to $37.7 million. A drop in overhead share next quarter would show the second-quarter workforce reduction is lowering ongoing costs.
Positives this quarter didn't test
Two standing growth drivers depend on details that Rambus only discusses on its conference call or in its quarterly filing, so the earnings release did not test them.
- Companion-chip share of product sales: management targets a mid-double-digit share by the fourth quarter after stalling near 11% last quarter; the call Q&A will show if the mix rose.
- Hyperscaler Silicon IP design wins: contract and other revenue grew 34.7% to $27.0 million, but the split of Silicon IP across royalties and contracts requires call commentary.
🐻 Bear Case
Inventory Nearly Doubled While Product Margin Fell
Rambus frames its chip business around differentiated products for data centers and steady profitability. Yet the cost of making those chips is rising faster than sales, and unsold stock on the balance sheet is building rapidly. By our math, product gross margin — the profit left from chip sales after manufacturing costs — fell 3.0 percentage points from a year ago to 60.2%.
- Inventories on the balance sheet: $87.2 million, up 97.8% from $44.1 million at the end of 2025
- Quarterly inventory increase: up $12.4 million from $74.8 million in the second quarter
- Cost of product revenue: 39.8% of product sales, up from 36.8% a year ago by our math
This matters because the San Jose company has ruled out raising chip prices during the memory shortage, leaving unit volume and newer companion chips to offset annual price drops on older parts. If server builders are ordering ahead of need while lead times are long, a near-doubling of inventory leaves the chipmaker exposed to a sudden order slowdown.
What to watch: fourth-quarter inventories and product cost of sales when the full report arrives. A product gross margin falling below 60% would show that newer companion chips carry lower margins or that older chip prices are falling faster.
Lumpy Royalties Hold Back the Fourth-Quarter Plan
Alongside physical chips, Rambus collects royalties from patent and technology licenses. Because accounting rules depend on when license renewals are signed, royalty revenue swings from quarter to quarter. In the third quarter, royalties fell 8.7% from the prior quarter to $77.0 million, beating the $69 million to $75 million outlook. Beating that range says the third-quarter outlook was cautious, not that the renewal swings have ended.
For the fourth quarter, the company forecasts royalties of $68 million to $74 million, a further 7.7% drop from this quarter at the middle of the range and down 0.9% from a year ago by our math. That $6.0 million sequential step-down absorbs more than a third of the planned $15.7 million gain in product sales. What to watch: fourth-quarter royalties against the $71 million midpoint. Another drop would confirm that licensing timing is dragging on total growth.
Risks this quarter didn't answer
Four standing risks around supply chains, customer concentration and future server designs received no new data in the earnings release, though Rambus introduced an "industry-leading PMIC for LPDDR6 SOCAMM2 and data center-class Root of Trust security IP".
- Back-end assembly tightness: management called outsourced packaging a constraint through 2027; the conference call will show if lead times lengthened further.
- Intel and AMD server launch timing: the 2027 revenue step-up from next-generation MRDIMM memory modules depends on processor schedules discussed on the call.
- Customer concentration: whether the largest customer stayed at 42% of accounts receivable will appear in the quarterly filing's footnote.
- Low-power memory module shift: launching a power chip for LPDDR6 SOCAMM2 — a compact memory module format — adds a product, but the call must address whether the format uses fewer Rambus chips per server.
💲 Other KPIs
Cash left after capital spending rose 14.1% from a year ago and jumped from $49.0 million last quarter, by our math. Operating cash flow hit a record $102.5 million while equipment spending was $11.2 million, below the $13 million plan. Free cash flow reached 41.8% of revenue, up from 23.6% in the second quarter.
Deferred revenue — cash customers have paid for contracts not yet recognised as sales — rose 52.9% from last quarter and 36.0% from a year ago, by our math. After shrinking in the first two quarters of 2026 as older contracts converted into revenue, the balance added $11.2 million this quarter.
Sales from silicon intellectual property licenses and engineering contracts grew 34.7% from a year ago and 12.7% from last quarter, by our math. That marks the third straight quarter of sequential growth, up from $21.8 million in the fourth quarter of 2025, and landed inside the company's $25 million to $31 million outlook.
🔮 Guidance
New. The plan calls for $230 million at the middle of the range, up 5.4% from this quarter and 20.9% from a year ago by our math. Rambus has beaten its revenue midpoint for six straight quarters, by an average of 3.4% over the last four; if the pattern holds, fourth-quarter revenue would reach about $237.8 million by our math.
New. At the $130 million middle of the range, chip sales grow 13.7% from the third quarter and 34.3% from a year ago by our math. That represents a sharp step-up from the 22.5% yearly pace recorded in the third quarter, even against a year-ago fourth quarter when product sales rose 32%.
New. The forecast points to $71 million at the middle of the range, down 7.7% from this quarter and 0.9% lower than a year ago by our math. It is the second straight quarter management has planned for a sequential drop in licensing royalties.
New. The $29 million middle of the range equals 7.3% growth from this quarter and 33.1% growth from a year ago by our math, continuing the steady climb in silicon intellectual property licensing.
New. Operating costs excluding one-offs (which include cost of sales and overhead) are planned at $122 million at the middle of the range, up 5.1% from this quarter's $116.1 million and up 18.2% from a year ago by our math, rising alongside higher product shipments.
New. Reported total costs and expenses are set for $141 million at the middle of the range, up 4.7% from this quarter and 18.1% from a year ago by our math. The plan includes $18.2 million of stock-based compensation, up from $17.1 million in the third quarter.
New. Profit per share excluding one-offs is planned at $0.88 at the middle of the range, up 4.8% from this quarter and 29.4% from a year ago by our math. The outlook assumes a 16% tax rate and 109 million diluted shares.
New. Reported profit per share is planned at $0.72 at the middle of the range, up 4.3% from this quarter and 24.1% from a year ago by our math, assuming a 17.5% tax rate.
❓ Key Questions
Did companion chips grow as a share of product sales?
Last quarter, newer companion chips stalled at a low double-digit share of product sales while management targeted a mid-double-digit share by year-end. Without this figure on the call, investors cannot tell if fourth-quarter chip growth comes from new products or general server demand.
Why did inventories nearly double while product margins fell?
Inventories reached $87.2 million, up 98% since December, while product gross margin sits at 60.2%, down 3.0 percentage points from a year ago. Management has not explained whether the inventory build reflects strategic buffer stock or slower customer take-up.
Why is overhead still rising after the second-quarter layoffs?
Rambus completed a $3.3 million workforce reduction in the second quarter to lower expenses, yet sales, general and administrative costs still rose 29% from a year ago to $37.7 million. We do not know if last quarter's jump in outside professional fees is now permanent.
What is the dollar revenue of the Silicon IP business?
Rambus splits its silicon intellectual property revenue across royalties and contract sales without giving a total dollar figure. Disclosing the exact split would show how much of the third-quarter royalty beat came from new chip design wins versus older patent renewals.