The convertible bond market is having its loudest year since the post-pandemic boom — and the past month showed why. Akamai priced $3.0 billion in zero-coupon convertibles on May 19. ON Semiconductor launched $1.3 billion in convertible senior notes on May 6. Ciena upsized its offering to $2.5 billion of zero-coupon convertibles on June 8. Three pricings in roughly four weeks, all with names large enough to matter, and every one of them stamped with a coupon of 0.00%.
A search of SEC EDGAR for 8-K filings whose press releases announce the pricing of convertibles returned 43 such filings between January 1 and June 16, 2026, versus 30 over the same window last year — a 43% year-over-year jump in deal count. That makes 2026 the strongest start to a convertible year since 2021, when the post-pandemic SPAC-and-converts boom drove deal counts well above the trailing average.
Why companies are turning to converts
Convertible bonds are corporate debt that comes with an embedded equity option — the bondholder can convert into shares of the issuer’s stock if the share price climbs above a strike. In exchange for that upside, the investor accepts a much lower coupon than a straight bond would carry. The bondholder gives up current income for optionality; the company gets cheap debt and defers the dilution.
That trade is especially attractive in 2026. Investment-grade corporate borrowing costs sit well above where they were in 2020–21, and high-yield issuers face the same headwind. A coupon of 4.5%–6.0% on a five-year straight bond is the going rate for a single-A or BBB-rated tech company. Convertibles let the same issuer pay zero — and Ciena, Akamai, and ON Semi did exactly that in the past five weeks.
Investors are willing to accept a zero coupon because they get long-dated call options on the issuer’s stock instead. Hedge funds running convertible arbitrage strategies — long the convertible, short the underlying stock — buy these bonds for the embedded volatility, not the income.
Inside the recent deals
| Issuer | Priced | Size | Coupon | Premium | Maturity |
|---|---|---|---|---|---|
| Ciena (CIEN) | Jun 8, 2026 | $2.5B* | 0.00% | 60.0% | Sept 2031 |
| Akamai (AKAM) | May 19, 2026 | $3.0B* | 0.00% | 42.5% | May 2030 / 2032 |
| ON Semi (ON) | May 6, 2026 | $1.3B | 0.00% | n/d | 2031 |
| Super Micro (SMCI)† | Jun 11, 2026 | $3.75B | 7.00% | n/a | Mandatory 2029 |
Ciena is the most striking. The networking-equipment maker priced $2.5 billion of 0.00% convertible senior notes due September 2031, upsized from a $2.0 billion initial size. The conversion price of about $746.66 per share sat 60% above the $466.67 reference price on June 8. Ciena plans to use $1.14 billion of the net proceeds to repay term loan debt and the remainder for share repurchases and supply-chain investment. Zero cash interest, term-loan refinancing, and a buyback funded by the deal — the trifecta convertible bankers sell to CFOs.
Akamai went further, splitting $3.0 billion across two zero-coupon tranches: $1.5 billion due 2030 (42.5% conversion premium) and $1.5 billion due 2032. The bulk of net proceeds funds an accelerated buildout of the company’s Cloud Infrastructure Services platform; another $203 million pays the hedge cost and $350 million repurchases stock at the $141.34 reference price. Investors funded essentially all of Akamai’s near-term capex without taking on a single dollar of cash-paying interest expense.
ON Semiconductor priced $1.3 billion of 0% convertible senior notes due 2031 on May 6, a private 144A offering placed with qualified institutional buyers — another zero-coupon refinancing tool for a mature investment-grade name.
Super Micro Computer’s $7.0 billion equity-and-equity-linked combo on June 11 sits in a slightly different bucket — the $3.75 billion of depositary shares represents a 7.0% mandatory convertible preferred, which by design must convert into common stock at maturity. That’s closer to equity than to a traditional convertible note, but the same logic applies: cheap rate, equity-deferred dilution, and a way to fund $39 billion of AI server orders the company has booked in recent weeks.
Issuance is back to 2020-21 levels
The chart counts deal-announcement filings, not dollar volume, but it captures the cadence: convertible pricings collapsed in 2022 as the Fed hiked, recovered slowly through 2024, dipped in 2025, and have now surged back to within striking distance of 2020-21 levels. Aggregate principal in the four deals above alone exceeds $10 billion, and the calendar still has six months to run.
The risks for investors and issuers
For investors, the convertible bid this cycle is being driven by hedge-fund convertible arbitrage and outright long-only crossover funds. The bonds work as long as equity volatility stays elevated and the issuer’s stock has a credible upside path. When neither holds — flat stock, falling vol — convertible holders end up with a low-coupon credit instrument trading like a long-duration bond.
For issuers, the cheap coupon is real but the dilution risk is deferred, not avoided. Ciena’s $2.5B convert at a 60% premium converts to roughly 3.3 million shares at $746.66; if Ciena trades there in 2031, those shares hit the float. Companies often pair issuance with convertible note hedge and warrant transactions — Ciena spent $100M of its net proceeds on exactly that — to raise the effective conversion price and blunt the dilution. The result is a cap structure with multiple moving parts that long-only equity investors have to model carefully.
Refinancing risk is the other watch item. A 0% convertible due 2030 only stays cheap if the issuer’s stock cooperates. If the share price sits well below the strike at maturity, holders take their principal back in cash and the issuer rolls into a market that may demand a real coupon. Akamai, Ciena, and ON Semi have all locked in zero cash interest for five-to-six years; the question is what the refinancing wall looks like in 2030 and 2031.
What it means for the market
The takeaway is not that converts are euphoric. Forty-three pricings in five and a half months is healthy, not frothy. What it does signal is that the corporate financing menu has been recalibrated for a higher-for-longer rate regime. Treasurers who in 2020 would have issued straight investment-grade debt are now reaching for hybrid structures because the math on coupon cost dominates the math on dilution. Until the front end of the curve drops materially, expect the convertible pipeline to keep filling.
For background on how convertible bonds work as instruments, see ECMSource’s prior explainers: Convertible Bonds: How Debt and Equity Merge in One Security and Convertible Bonds Explained: When Debt Turns Into Stock.
Sources
- SEC EDGAR full-text search, 8-K filings with “announces pricing of” and “convertible,” Jan-Jun 2026.
- Ciena Corporation 8-K Exhibit 99.1, Pricing of Upsized Convertible Senior Notes, June 8, 2026.
- Akamai Technologies 8-K Exhibit 99.1, Pricing of Upsized Offering of Convertible Senior Notes, May 19, 2026.
- ON Semiconductor 8-K, Commencement of $1.3B Convertible Senior Notes Offering, May 6, 2026.
- Super Micro Computer 8-K Exhibit 99.2, Pricing of Equity and Equity-linked Financing Transactions, June 11, 2026.
Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.