stockholders. Purchases will only be made at less than net asset value per share, thereby increasing the net asset value of shares held by the remaining stockholders. Shares so acquired may be held as treasury stock available for stock distributions, or may be retired.
4. Investment Transactions—The aggregate cost of securities purchased and the aggregate proceeds of securities sold during the six months ended June 30, 2020, excluding short-term investments, were $41,341,569 and $36,635,014, respectively.
As of June 30, 2020, the tax cost of investments was $408,011,753. Net unrealized appreciation was $500,302,379 consisting of gross unrealized appreciation and gross unrealized depreciation of $514,065,089 and $13,762,710, respectively.
5. Affiliated Companies—Plymouth Rock is an affiliated company as defined in the Investment Company Act of 1940 due to the Corporation’s ownership of 5% or more of the company’s outstanding voting securities. During the six months ended June 30, 2020, unrealized appreciation from the Corporation’s investment in Plymouth Rock decreased by $17,054,400 and the Corporation received dividends of $7,081,555 from Plymouth Rock. The Chief Executive Officer of the Corporation is a director of Plymouth Rock. The President of the Corporation is a director of certain subsidiaries of Plymouth Rock.
6. Restricted Securities—The Corporation may from time to time invest in securities the resale of which is restricted. On June 30, 2020, the Corporation’s only restricted security consisted of 28,424 shares of Plymouth Rock Class A stock that were acquired on December 15, 1982 at a cost of $710,600. This security had a value of $198,968,000 at June 30, 2020, which was equal to 21.9% of the Corporation’s net assets. The Corporation does not have the right to demand registration of this security.
7. Bank Line of Credit—The Corporation has entered into a $25 million uncommitted, secured revolving line of credit with UMB Bank, n.a. (“UMB”), the Corporation’s custodian. All borrowings are payable on demand of UMB. Interest on any borrowings is payable monthly at a rate based on the federal funds rate, subject to a minimum annual rate of 2.50%. No borrowings were made during the six months ended June 30, 2020.
8. Compensation and Benefit Plans—The aggregate compensation expense for all officers during the six months ended June 30, 2020 was $1,793,963, of which $1,250,003 was paid during the period.
Officers and other employees participate in a 401(k) profit sharing plan. The Corporation has agreed to contribute 3% of each participant’s qualifying compensation to the plan, which is immediately vested. Contributions in excess of 3% may be made at the discretion of the Board of Directors and vest after three years of service. During the six months ended June 30, 2020, the Corporation accrued $126,768 related to the plan.
The Corporation maintains an incentive compensation plan (the “2012 Plan”) which permits the granting of awards of unrestricted stock, restricted stock, restricted stock units and cash to full-time employees and non-employee directors of the Corporation. The 2012 Plan provides for the issuance of up to 1,000,000 shares of the Corporation’s Common Stock over the ten-year life of the 2012 Plan, of which 918,059 remain available for future grants at June 30, 2020. The 2012 Plan limits the amount of shares that can be awarded to any one person in total or within a certain time period. Any award made under the 2012 Plan may be subject to performance conditions. The 2012 Plan is administered by the Corporation’s Compensation and Nominating Committee.
Pursuant to the terms of the 2012 Plan, each non-employee director is awarded 500 shares of vested unrestricted Common Stock at initial election to the Board of Directors and annually after re-election at the Corporation’s annual meeting. During the six months ended June 30, 2020, non-employee directors were granted a total of 4,000 shares of Common Stock at a weighted average grant date value of $22.79 per share. The grant date value is the average of the high and low prices of the Corporation’s Common Stock on the grant date. The aggregate share value of $91,148 plus cash payments of $87,500 made to all non-employee directors are included in Directors’ fees expense in the accompanying Statement of Operations.