Tether, issuer of the USDT stablecoin, held $3.3 billion of reserve assets in excess to back the value of its stablecoins, the ​​firm reported in its Q2 attestation on Monday.

Signed by accounting firm BDO Italy, the attestation disclosed about $72.5 billion of exposure to U.S. Treasuries, including direct T-bill investments, repurchase agreements and deposits in money market funds.

The company’s bitcoin (BTC) holdings as of June 30 increased in dollar value to $1.67 billion from $1.5 billion three months earlier, according to the filing, though the number of tokens held was not disclosed.

Tether said its operational profits exceeded $1 billion for the second quarter. In May, the firm reported $1.45 billion in “net profits” in Q1.

Tether is the issuer behind the $83 billion USDT, the largest stablecoin by market capitalization, and some smaller stablecoins. USDT is a key piece of the crypto ecosystem facilitating trading and asset transfers.

Issuing fiat-backed dollar-pegged stablecoins is a lucrative business due to rising U.S. government bond yields, the primary reserve asset for USDT. Tether’s reported profits are close those of asset management giant BlackRock – with more than $9 trillion in assets under management (AUM) – which booked operating income of just over $1.6 billion in Q2.

Tether, however, continues to receive a fair amount of scrutiny for its opaque reserve management and lack of independent audits – a deeper financial analysis than attestations.

Read more: Reviewing the Tether Documents