In the six months ended June 30, 2021, we recorded grant income of $4.7 million, compared to $3.1 million in the six months ended June 30, 2020. The increase of $1.6 million was primarily due to higher income from Austrian research and development incentives.
Interest Income and Expense
Interest income was less than $0.1 million for the three and six months ended June 30, 2021, compared to interest income of $0.1 million and $0.4 million for the three and six months ended June 30, 2020, respectively. The decrease in the three and six month ended June 30, 2021, despite higher cash balances, was due to the drop in interest rates in the United States and Europe. Interest income represents interest from cash and cash equivalents held in US dollars resulting from the proceeds from the issuance of common and preferred stock, including our IPO and recent follow-on public offering as well as payments received under our Collaboration Agreement with Gilead. During the three and six months ended June 30, 2021 our cash, cash equivalents and restricted cash were mainly held in dollars at U.S. investment grade financial institutions or in money market funds. In addition smaller amounts were held in euros at our Austrian subsidiary that produced no material interest income due the low or zero interest rate policy in the European Monetary Union.
Interest expenses for loans from government agencies were $0.2 million for the three months ended June 30, 2021 and for the three months ended June 30, 2020. Interest expenses for loans from government agencies were $0.4 million for the six months ended June 30, 2021 and for the six months ended June 30, 2020. Interest expense was recorded at the market rate of interest, which exceeded the contractual interest.
Other Income and Expenses
Other expenses were $0.2 million for the three months ended June 30, 2021, compared to other income of $0.6 million for the three months ended June 30, 2020. The decrease in the three months ended June 30, 2021 resulted primarily from realized exchange rate differences and foreign currency remeasurements. In addition, in April 2020, we applied for support under the Corona Short-term Work Program in Austria to mitigate the financial impact of the COVID 19 pandemic. In the three months ended June 30, 2020, we recognized $0.2 million in other operating income from non-refundable subsidies under this support program which contributes to the decrease of other income and expenses in the three months ended June 30, 2021.
Other expenses were $0.2 million for the six months ended June 30, 2021, compared to other income of $0.6 million for the six months ended June 30, 2020. The decrease in the six months ended June 30, 2021 resulted primarily from realized exchange rate differences and foreign currency remeasurements. In addition, in April 2020, we applied for support under the Corona Short-term Work Program in Austria to mitigate the financial impact of the COVID 19 pandemic. In the six months ended June 30, 2020, we recognized $0.2 million in other operating income from non-refundable subsidies under this support program which contributes to the decrease of other income and expenses in the six months ended June 30, 2021.
Liquidity and Capital Resources
Since our inception in 2011, we have funded our operations primarily through private placements of our convertible preferred stock and proceeds from our IPO and follow-on public offering, from grants, research incentives and borrowings under various agreements with public funding agencies, and from an upfront payment, milestone payments and reimbursement of research and development expenses pursuant to the Collaboration Agreement with Gilead.
We have raised gross proceeds of approximately $142.5 million from the issuance of our convertible preferred stock and $22.2 million from non-refundable upfront and milestone payments pursuant to the Collaboration Agreement with Gilead. In April 2019, we completed our IPO in which we issued and sold 6,000,000 shares of our common stock, at $14.00 per share, for gross proceeds of $84.0 million, or net proceeds of $74.6 million. On December 11, 2020, we completed a follow-on public offering in which we issued 3,910,000 shares of our common stock, at $11.75 per share, and 2,978 shares of our Series A convertible preferred stock, at $11,750.00 per share, for net proceeds of $75.0 million