First-quarter figures from The Institute of London Underwriters show the aggregate tonnage of ships lost up 105% from the same period last year. Tonnage lost in this year's first quarter leapt to 295,547 gross tons for ships of 500 gross tons and above. The ILU described the trend as "disturbing" and warned that the figure most likely will increase as partial losses are reclassified as constructive total losses. . . .A new superagency is on the cards at Lloyd's of London with the proposed merger of Murray Lawrence Members Agency Ltd. and Bankside Members Agency Ltd. If the proposal is accepted by shareholders and Lloyd's regulators, the agency will be responsible for (British pounds) 730 million ($1.2 billion) in capacity this year, more than 7% of the market's 1997 capacity of (British pounds) 10.3 billion ($17.64 billion). . . .Ratings agency Standard & Poor's Corp. has equalized its claims-paying ability rating of French insurer AXA-UAP Groupe at AA- following the merger of AXA and UAP. This rating is a downgrade of AXA's rating from AA, but a boost over UAP's former A rating. S&P based its decision on several factors, including AXA-UAP's global presence, a strong strategic focus on insurance, high-caliber senior management and potential for improved profitability. But S&P warned that the group's capitalization, though "satisfactory" from a risk-based perspective, is "somewhat restricted" for an organization in the 'AA' range. Philippe Deriux, deputy financial officer at AXA-UAP, said the size of the organization's capitalization is "absolutely satisfactory to cover the insurance risks," adding that the insurer will not try to raise capital in the short term, as it would dilute shareholders' returns. . . .London broker FirstCity Insurance Brokers Ltd. has turned over some control of the organization's future to its staff by setting up an employee trust fund. All employees are eligible to join the plan, with their share of the value of assets in the fund determined by several factors. The trust controls 65% of the organization's equity and gives employees a say in major decisions affecting the company, including merger activity. . . .Terms of The Tokio Marine & Fire Insurance Co. Ltd.'s sale of its Houston General Insurance Co. unit to U.K. multiline insurer Commercial Union Assurance Co. P.L.C. are yet to be finalized, but will depend partly on the reinsurance for the runoff of the existing business. Fort Worth, Texas-based Houston General specializes in small to medium-size commercial coverages, and had policyholder surplus of $38 million at the end of last year . . .London-based Colonia Baltica Insurance Ltd., created last November when Colonia Insurance Co. (UK) Ltd. and Baltica Insurance Co. (UK) Ltd. merged, has posted a (British pounds) 2.3 million ($3.9 million) profit for 1996. Colonia Baltica is jointly owned by Cologne-based Colonia Versicherung A.G., a member of the AXA-UAP Groupe, and Trygg-Baltica Forsikring A/S of Copenhagen.