For the first time, the most systemically important U.S. banks have reported data showing compliance with the liquidity coverage ratio, or LCR, a regulation that some bankers have called the most constraining post-crisis rule.

By Aug. 29, seven of the eight U.S. banks that have been classified as global systemically important banks reported LCR results. Among the filings, State Street Corp. reported the lowest ratio at 109%, meaning the bank had a stash of high-quality liquid assets that equaled 109% of its expected net cash outflows over a 30-day stress scenario. Goldman Sachs Group Inc. reported the highest ratio at 128%. Bank of New York Mellon Corp. has not yet reported.

The six non-trust banks — Goldman Sachs, Bank of America Corp., Citigroup Inc., JPMorgan Chase & Co., Morgan Stanley and Wells Fargo & Co. — all reported ratios between 115% and 128%, well above the regulatory minimum of 100%. In an Aug. 29 note, Steven Chubak, an analyst for Nomura Instinet, wrote that the high ratios suggested another regulation, such as resolution planning, was forcing banks to hold more liquidity than would be required by LCR alone.

Chubak also noted that the banks held relatively low levels of "Level 2 assets," a classification of high-quality liquid assets. Level 2 assets tend to be more volatile than Level 1 assets but are still considered generally stable and liquid. Level 2 assets cannot constitute more than 40% of a bank's total high-quality liquid assets, and Chubak noted that the six non-trust G-SIBs reported a Level 2 asset concentration of just 14%, suggesting they will have ability to buy mortgage-backed securities that the Federal Reserve plans to sell in the coming months. JPMorgan in particular stood out as being able to take advantage of the higher-yielding securities as Level 2 assets accounted for just 3.7% of its high-quality liquid assets, giving the bank room to purchase up to $230.87 billion of mortgage securities, according to Chubak's analysis.