Debate in Congress over the future of the U.S. Export-Import Bank is coming to a head. Absent congressional action, Ex-Im will be unable to provide new loans or guarantees to American exporters after its charter expires on Sept. 30.

Ex-Im’s critics have not been shy, noting that most U.S. exports are financed by the private sector. That’s true, but in today’s fiercely competitive and highly regulated global markets, the question of trade finance isn’t that simple.

In fact, Ex-Im support is often required to secure commercial financing for a small firm’s exports. It’s required to qualify for overseas bids on major projects. It’s required to match financing terms provided by competitors from every other major trading nation.

Consider these examples of small, medium-sized, and large companies that would be shut out of export markets or lose major sales without Ex-Im:

ProGauge Technologies in Bakersfield, Calif., makes machinery that injects steam into heavy oil wells to make it easier to pump. President Don Nelson explains how he uses Ex-Im’s working capital guarantees: “Wells Fargo requires us to get an Ex-Im guarantee and put up 10 percent collateral. Without Ex-Im, Wells Fargo would require us to put up 100 percent collateral, and we would have no money available for operations.”

The challenge for small businesses is that U.S. commercial banks simply do not allow American companies to use foreign receivables or inventory as collateral. Far from crowding out the private sector, Ex-Im working capital guarantees let private banks extend loans and guarantees that they wouldn’t be able to make otherwise.

Bridge to Life Solutions in Columbia, S.C., uses the most widely utilized Ex-Im product for small businesses: credit insurance. The firm insures orders for state-of-the-art cold storage organ transplant solutions and began exporting thanks to Ex-Im.

John Bruens, Chief Commercial and Business Development Officer for Bridge to Life, says: “Without Ex-Im, I would have to tell my customers, ‘prepay everything up front, or we can’t do business.’” By purchasing credit insurance from Ex-Im for the firm’s foreign receivables, Bridge to Life has been able to extend credit terms to its international customers — and sales soared. As many small businesses can explain, if you can’t offer terms, you won’t make the sale.

South African railway Transnet recently put out a bid for 466 diesel electric locomotives at a total contract price of $750 million. As is common in such bids, one requirement was that the supplier must finance a significant portion of the transaction.

Backed by aggressive export financing provided by China’s export credit agency, Chinese locomotive manufacturers won half the order. In March, General Electric won the order for the other 233 locomotives but only because Ex-Im support was available to level the financial playing field. Without Ex-Im, GE would have lost the entire order — with real world consequences for workers at its Erie, Pa., plant.

Then there’s Saudi Arabia’s Sadara Chemical Company, which will be the largest integrated petrochemical complex ever built in a single phase when all units are up and running in 2016. Like other modern industries such as aircraft manufacturing and nuclear power, vast scale is key to Sadara’s economics.

Sadara’s $12.5 billion in project financing set a record for the petrochemicals sector. Funds came from diversified sources: international and local commercial banks, Islamic financial institutions, a $2 billion sukuk (Islamic bond) issuance, and Ex-Im.

The Ex-Im loan provided support for $3.8 billion in U.S. exports used in the project, including power transformers, electrical heaters, grounding monitor panels, junction boxes, cable trays and more. Manufacturing these goods was an army of nearly 20,000 American workers with more than 80 U.S.-based companies, including 20 small businesses.

Why can’t financing for huge projects such as Sadara be left entirely to the private sector? On large, long-term foreign project financing deals, when a project is put out for bid, it is standard practice that the bid must include financing or guarantees from an official export credit agency such as Ex-Im. If such financing is unavailable, the company is excluded from the bid.

In short, Ex-Im support isn’t just something that American companies like to have. To secure commercial financing for a small firm’s exports, to qualify for overseas bids, or to match terms provided by competitors from every other major trading nation, Ex-Im is indispensable.

Myron Brilliant is executive vice president and head of international affairs at the U.S. Chamber of Commerce.