During the third quarter of 2020, we purchased 4,672,897 shares of Entasis common stock as well as warrants to purchase 4,672,897 additional shares of its common stock for approximately $12.5 million in cash. Innoviva has a right to designate 2 members to Entasis’ board. As of March 31, 2021 and the date hereof, 0 Innoviva designees are serving on Entasis’ six-member board. As of March 31, 2021, we owned approximately 51.0% of Entasis’s common stock.
The investment in Entasis provides Innoviva the ability to have significant influence, but not control over Entasis’ operations. Based on our evaluation, we determined that Entasis is a VIE, but Innoviva is not the primary beneficiary of the VIE. We elected the fair value option to account for both Entasis's common stock and warrants at fair value. The fair value of Entasis's common stock is measured based on its closing market price at each balance sheet date. The warrants have an exercise price of $2.50 per share for those warrants acquired in the second quarter of 2020 and an exercise price of $2.675 per share for the warrants acquired in the third quarter of 2020. The warrants are exercisable immediately within five years from the issuance date of the warrants and include a cashless exercise option. We use the Black-Scholes-Merton pricing model to estimate the fair value of these warrants.
As of March 31, 2021, the fair values of Entasis’s common stock and warrants were estimated at $40.0 million and $26.6 million, respectively. As of December 31, 2020, the fair values of Entasis’s common stock and warrants were estimated at $46.1 million and $31.9 million, respectively. The total fair value of both financial instruments in the amount of $66.6 million and $78.0 million was recorded as equity and long-term investments on the consolidated balance sheets as of March 31, 2021 and December 31, 2020, respectively. We recorded $11.5 million unrealized loss from the changes of fair value as changes in fair values of equity and long-term investments, net on the consolidated statements of income for the three months ended March 31, 2021.
Equity Investment in InCarda
In October, 2020, TRC purchased 20,469,432 shares of Series C preferred stock and warrants to purchase 5,117,358 additional shares of Series C preferred stock of InCarda Therapeutics, Inc. for $15.0 million. $0.8 million was incurred for investment due diligence costs and recorded as part of the equity investment on the consolidated balance sheets. InCarda is a privately held biopharmaceutical company focused on developing inhaled therapies for cardiovascular diseases. As of March 31, 20201 and as of the date hereof, 1 of InCarda’s 8 board members is designated by TRC. As of March 31, 2021, TRC held 13.0% of InCarda‘s outstanding equity.
The investment in InCarda does not provide TRC the ability to control or have significant influence over InCarda's operations. Based on our evaluation, we determined that InCarda is a VIE, but TRC is not the primary beneficiary of the VIE. We account for our investment in the Series C preferred shares in InCarda using the measurement alternative. Under the measurement alternative, the equity investment is initially recorded at its allocated cost, but the carrying value may be adjusted through earnings upon an impairment or when there is an observable price change involving the same or a similar investment with the same issuer. The warrants are recorded at fair value and subject to remeasurement at each balance sheet date. The warrants are exercisable immediately with an exercise price of $0.7328 per share and expire on October 6, 2021, one year from the issuance date. We use the Black-Scholes-Merton pricing model to estimate the fair value of the warrants with the following input assumptions: the exercise price of the warrants, the risk-free interest rate computed based on the U.S. Treasury yield, the remaining contractual term as the expected term, and the expected stock price volatility calculated based on the historical volatility of the common stock of its peer companies.
As of March 31, 2021 and December 31, 2020, the fair value of InCarda’s warrants was estimated at $0.7 million and $1.1 million, respectively, and recorded as equity and long-term investments on the consolidated balance sheets. We recorded $0.5 million unrealized loss from the changes of fair value as changes in fair values of equity and long-term investments, net on the consolidated statements of income for the three months ended March 31, 2021. There was 0 impairment or other change to the value of InCarda’s Series C preferred stock of $15.8 million as of March 31, 2021.
Equity Investment in ImaginAb
On March 18, 2021, TRC entered into a securities purchase agreement with ImaginAb, Inc. to purchase 4,051,724 shares of ImaginAb Series C preferred stock for $4.7 million. On the same day, TRC also entered into a securities purchase agreement with one of ImaginAb’s common stockholders to purchase 4,097,157 shares of ImaginAb common stock for $1.3 million. ImaginAb is a privately held biotechnology company focused on clinically managing cancer and autoimmune diseases via molecular imaging. $0.4 million was incurred for investment due diligence costs and execution and recorded as part of the equity investment on the consolidated balance sheets. As of the date hereof, 1 of ImaginAb’s 7 board members is designated by TRC. As of March 31, 2021, TRC held 13.0% of ImaginAb equity ownership.