When tanker investors, analysts, and company executives talk about freight rates, they almost always reference an index. The most commonly cited one for crude oil tankers is the Baltic Dirty Tanker Index, usually abbreviated as the BDTI. If you follow tanker stocks like Frontline ($FRO), DHT Holdings ($DHT), International Seaways ($INSW), or Teekay Tankers ($TNK), understanding what the BDTI is and how to read it will make every earnings call, analyst note, and market update significantly more useful.
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What the Baltic Exchange Is
Before explaining the index, it helps to understand who publishes it. The Baltic Exchange is a London-based membership organization that has been setting shipping freight benchmarks since the 1700s. It is not a financial exchange where you buy and sell contracts. It is a market data and information organization that collects daily rate assessments from a panel of shipbrokers and publishes standardized indices used as reference points across global shipping.
The Baltic Exchange publishes dozens of indices covering dry bulk shipping, container shipping, liquefied natural gas shipping, and tanker shipping. For crude oil tanker investors, the two most relevant are the Baltic Dirty Tanker Index, which covers crude oil movements, and the Baltic Clean Tanker Index, which covers refined petroleum products like gasoline and diesel.
What Dirty Means in This Context
In shipping, crude oil is called dirty cargo because it leaves residue in the ship’s tanks that requires cleaning between cargoes. Refined products like gasoline and jet fuel are called clean cargo because they are cleaner to carry and the tanks can be more easily cleaned between different product types.
So the Baltic Dirty Tanker Index specifically tracks the cost of moving crude oil, the unrefined stuff that comes out of the ground and gets shipped to refineries. This is the market where VLCCs, Suezmax tankers, and Aframax tankers compete, and it is the market where the publicly traded crude tanker companies earn most of their revenue.
How the BDTI Is Calculated
The Baltic Exchange collects daily rate assessments from a panel of independent shipbrokers for a set of defined trade routes. Each route has a specific vessel type, a loading port, a discharge port, and an agreed cargo size. The brokers assess what it would cost to charter a vessel for that specific route on that specific day, based on their knowledge of actual market transactions happening in real time.
Those route assessments are then weighted and combined to produce the composite BDTI number, which is expressed as an index rather than a dollar figure. The base value of 1,000 was set back in the early history of the index, so a reading of 1,500 means rates are 50 percent above that base level, and a reading of 700 means they are 30 percent below it.
The specific routes assessed for the BDTI include the key global crude trade lanes: Middle East Gulf to Asia, West Africa to the US Gulf, North Sea routes, Caribbean crude movements, and Mediterranean trades. Each route uses the vessel class most commonly employed on that lane, ranging from VLCCs down to Aframax tankers.
How to Read BDTI Movements for Tanker Stocks
A rising BDTI means freight rates are increasing, which typically means tanker companies are earning more revenue per voyage. A falling BDTI means rates are declining.
The relationship between the BDTI and tanker stock prices is real but not perfectly mechanical. Stocks often move in anticipation of rate changes rather than reacting to them after the fact. During the Hormuz crisis of 2026, BDTI readings moved to historically extreme levels as VLCC rates shattered records, and tanker equities had already run significantly before the index peaks were reached.
Experienced tanker investors pay more attention to the rate trajectory and the rate context than to any single day’s reading. Is the BDTI at 2,000 and heading higher because a disruption is still developing? Or is it at 2,000 and declining because the market is pricing in a resolution? The direction and the narrative matter as much as the level.
BDTI vs Individual Route Rates
Because the BDTI is a composite index, it can sometimes give a blurry picture of what is happening in a specific segment. A company like DHT Holdings ($DHT) that operates almost exclusively VLCCs cares primarily about the TD3C route, which is the Middle East Gulf to China VLCC benchmark. A Suezmax-focused operator cares about different routes. The composite BDTI can move up while VLCC-specific rates move down, or vice versa, depending on what is driving the composite.
For this reason, analysts and investors who follow specific tanker companies also track individual route assessments alongside the composite index. The TD3C rate for VLCCs and the TD20 rate for Suezmax tankers are among the most closely watched individual benchmarks.
Where to Find the BDTI
The Baltic Exchange publishes daily rate assessments on its website, though full access requires a subscription. Many financial data providers including Bloomberg, Reuters, and specialized shipping platforms like Clarksons Platou and Fearnleys republish the data for their subscribers.
For free access, financial news sites often report on significant BDTI moves, especially when the index reaches notable highs or lows. The Hellenic Shipping News website regularly covers Baltic Exchange data and is one of the more accessible free sources for staying current on rate trends.
I track BDTI trends and individual route movements as part of the SteamGauge dashboard here at TxZen. The Market Signals section is where I post weekly rate updates, and the TxZen Originals section covers deeper analysis when rate moves are significant enough to shift the investment thesis.
Not financial advice. Do your own research. I am an investor sharing my own framework for following this market.
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To see the BDTI in action, VLCC rates hit $423,736 in a single day during the early Hormuz crisis. That spike drove the index to levels not seen in two decades. Where rates stand now tells you whether the market has settled or is still elevated.