CWB’s Convertible Bond Strategy Looks Like Bonds Until the Equity Markets Fall, And Then It Trades Like Stocks

Marc Guberti

Wed, May 20, 2026 at 1:47 PM EDT 4 min read

Quick Read

• SPDR Bloomberg Convertible Securities ETF (CWB) trades like stocks in equity downturns, not bonds.

• CWB’s $5 billion fund concentrates heavily in tech and growth convertibles with equity-like downside risk.

• Investors treating CWB as bond protection should pair it with true core bond funds like SCHZ.

• The analyst who called NVIDIA in 2010 just named his top 10 stocks and SPDR Bloomberg Convertible Securities ETF wasn't one of them. Get them here FREE.

The pitch for the SPDR Bloomberg Convertible Securities ETF (NYSEARCA:CWB) is simple: collect a coupon, keep equity upside, sit between stocks and bonds. CWB has rewarded holders nicely on the way up. The risk most owners do not price in is that when equity markets crack, CWB stops trading like a bond fund and starts tracking the stocks its convertibles can convert into. CWB is mislabeled in many portfolios, and the asymmetry is the entire story.

What CWB actually owns

CWB tracks the Bloomberg US Convertible Liquid Bond Index. A convertible bond is corporate debt with an embedded call option to convert into the issuer's stock at a set strike. The coupon is usually 2% to 4%, and the conversion option drives returns. The fund holds roughly $5 billion in assets, charges 0.40%, and pays a distribution yield near 2.5%.

The analyst who called NVIDIA in 2010 just named his top 10 stocks and SPDR Bloomberg Convertible Securities ETF wasn't one of them. Get them here FREE.

The issuer base skews heavily toward tech and growth companies, where conversion features get used. CWB's credit exposure is a concentrated basket of equity-linked debt from issuers whose stocks move together when the NASDAQ wobbles, not the diversified investment-grade universe a core bond fund provides.

The bond floor falls out when you need it

A convertible's behavior depends on where the underlying stock trades versus the conversion price. When the stock sits well above the strike, the bond's delta approaches 1 and it moves nearly point-for-point with the equity. When the stock falls, the option value bleeds out and only the bond floor (the present value of future coupons and principal) supports the price. That floor sinks when credit spreads widen, which is exactly when equity markets are stressed.

CWB participates fully in equity rallies and follows equities down, just with less velocity. The bond character only shows up after the option value has been wiped out. In 2022, CWB lost roughly 17%, CWB performed worse than core bonds and only modestly better than the S&P 500. A smaller version played out a year ago: CWB fell from around $80 to about $71 last spring, roughly an 11% drawdown in about a week as equities sold off.