Secured negotiable obligations of the small business investment companies and negotiable obligations endorsed with recourse by the companies when adequately secured shall be eligible for purchase by insurance companies, investment companies and industrial development corporations, by the board of trustees administering any employee or profit-sharing trust, by the board of trustees of eleemosynary institutions and corporations, and by trustees and other fiduciaries. The same degree of care shall be exercised in making purchases of the obligations by fiduciaries as is required in making investments under §35-3-117.